
Changes in Version 2.27.29

   Changes since 2.17:
     * The Unison project now accepts donations via PayPal. If you'd like
       to donate, you can find a link to the donation page on the Unison
       home page (http://www.cis.upenn.edu/ bcpierce/unison/lists.html).
     * Several small fixes to the GTK2 UI to make it work better under
       Windows [thanks to Karl M for these].
     * The backup functionality has been completely rewritten. The
       external interface has not changed, but numerous bugs, irregular
       behaviors, and cross-platform inconsistencies have been corrected.
     * Some important safety improvements:
          + Added a new mountpoint preference, which can be used to
            specify a path that must exist in both replicas at the end of
            update detection (otherwise Unison aborts). This can be used
            to avoid potentially dangerous situations when Unison is used
            with removable media such as external hard drives and compact
            flash cards.
          + The confirmation of "big deletes" is now controlled by a
            boolean preference confirmbigdeletes. Default is true, which
            gives the same behavior as previously. (This functionality is
            at least partly superceded by the mountpoint preference, but
            it has been left in place in case it is useful to some
            people.)
          + If Unison is asked to "follow" a symbolic link but there is
            nothing at the other end of the link, it will now flag this
            path as an error, rather than treating the symlink itself as
            missing or deleted. This avoids a potentially dangerous
            situation where a followed symlink points to an external
            filesystem that might be offline when Unison is run
            (whereupon Unison would cheerfully delete the corresponding
            files in the other replica!).
     * Smaller changes:
          + Added forcepartial and preferpartial preferences, which
            behave like force and prefer but can be specified on a
            per-path basis. [Thanks to Alan Schmitt for this.]
          + A bare-bones self test feature was added, which runs unison
            through some of its paces and checks that the results are as
            expected. The coverage of the tests is still very limited,
            but the facility has already been very useful in debugging
            the new backup functionality (especially in exposing some
            subtle cross-platform issues).
          + Refined debugging code so that the verbosity of individual
            modules can be controlled separately. Instead of just putting
            '-debug verbose' on the command line, you can put '-debug
            update+', which causes all the extra messages in the Update
            module, but not other modules, to be printed. Putting '-debug
            verbose' causes all modules to print with maximum verbosity.
          + Removed mergebatch preference. (It never seemed very useful,
            and its semantics were confusing.)
          + Rewrote some of the merging functionality, for better
            cooperation with external Harmony instances.
          + Changed the temp file prefix from .# to .unison.
          + Compressed the output from the text user interface
            (particularly when run with the -terse flag) to make it
            easier to interpret the results when Unison is run several
            times in succession from a script.
          + Diff and merge functions now work under Windows.
          + Changed the order of arguments to the default diff command
            (so that the + and - annotations in diff's output are
            reversed).
          + Added .mpp files to the "never fastcheck" list (like .xls
            files).
     * Many small bugfixes, including:
          + Fixed a longstanding bug regarding fastcheck and daylight
            saving time under Windows when Unison is set up to
            synchronize modification times. (Modification times cannot be
            updated in the archive in this case, so we have to ignore one
            hour differences.)
          + Fixed a bug that would occasionally cause the archives to be
            left in non-identical states on the two hosts after
            synchronization.
          + Fixed a bug that prevented Unison from communicating
            correctly between 32- and 64-bit architectures.
          + On windows, file creation times are no longer used as a proxy
            for inode numbers. (This is unfortunate, as it makes
            fastcheck a little less safe. But it turns out that file
            creation times are not reliable under Windows: if a file is
            removed and a new file is created in its place, the new one
            will sometimes be given the same creation date as the old
            one!)
          + Set read-only file to R/W on OSX before attempting to change
            other attributes.
          + Fixed bug resulting in spurious "Aborted" errors during
            transport (thanks to Jerome Vouillon)
          + Enable diff if file contents have changed in one replica, but
            only properties in the other.
          + Removed misleading documentation for 'repeat' preference.
          + Fixed a bug in merging code where Unison could sometimes
            deadlock with the external merge program, if the latter
            produced large amounts of output.
          + Workaround for a bug compiling gtk2 user interface against
            current versions of gtk2+ libraries.
          + Added a better error message for "ambiguous paths".
          + Squashed a longstanding bug that would cause file transfer to
            fail with the message "Failed: Error in readWrite: Is a
            directory."
          + Replaced symlinks with copies of their targets in the Growl
            framework in src/uimac. This should make the sources easier
            to check out from the svn repository on WinXP systems.
          + Added a workaround (suggested by Karl M.) for the problem
            discussed on the unison users mailing list where, on the
            Windows platform, the server would hang when transferring
            files. I conjecture that the problem has to do with the RPC
            mechanism, which was used to make a call back from the server
            to the client (inside the Trace.log function) so that the log
            message would be appended to the log file on the client. The
            workaround is to dump these messages (about when
            xferbycopying shortcuts are applied and whether they succeed)
            just to the standard output of the Unison process, not to the
            log file.

   Changes since 2.13.0:
     * The features for performing backups and for invoking external
       merge programs have been completely rewritten by Stephane Lescuyer
       (thanks, Stephane!). The user-visible functionality should not
       change, but the internals have been rationalized and there are a
       number of new features. See the manual (in particular, the
       description of the backupXXX preferences) for details.
     * Incorporated patches for ipv6 support, contributed by Samuel
       Thibault. (Note that, due to a bug in the released OCaml 3.08.3
       compiler, this code will not actually work with ipv6 unless
       compiled with the CVS version of the OCaml compiler, where the bug
       has been fixed; however, ipv4 should continue to work normally.)
     * OSX interface:
          + Incorporated Ben Willmore's cool new icon for the Mac UI.
     * Small fixes:
          + Fixed off by one error in month numbers (in printed dates)
            reported by Bob Burger

   Changes since 2.12.0:
     * New convention for release numbering: Releases will continue to be
       given numbers of the form X.Y.Z, but, from now on, just the major
       version number (X.Y) will be considered significant when checking
       compatibility between client and server versions. The third
       component of the version number will be used only to identify
       "patch levels" of releases.
       This change goes hand in hand with a change to the procedure for
       making new releases. Candidate releases will initially be given
       "beta release" status when they are announced for public
       consumption. Any bugs that are discovered will be fixed in a
       separate branch of the source repository (without changing the
       major version number) and new tarballs re-released as needed. When
       this process converges, the patched beta version will be dubbed
       stable.
     * Warning (failure in batch mode) when one path is completely
       emptied. This prevents Unison from deleting everything on one
       replica when the other disappear.
     * Fix diff bug (where no difference is shown the first time the diff
       command is given).
     * User interface changes:
          + Improved workaround for button focus problem (GTK2 UI)
          + Put leading zeroes in date fields
          + More robust handling of character encodings in GTK2 UI
          + Changed format of modification time displays, from modified
            at hh:mm:ss on dd MMM, yyyy to modified on yyyy-mm-dd
            hh:mm:ss
          + Changed time display to include seconds (so that people on
            FAT filesystems will not be confused when Unison tries to
            update a file time to an odd number of seconds and the
            filesystem truncates it to an even number!)
          + Use the diff "-u" option by default when showing differences
            between files (the output is more readable)
          + In text mode, pipe the diff output to a pager if the
            environment variable PAGER is set
          + Bug fixes and cleanups in ssh password prompting. Now works
            with the GTK2 UI under Linux. (Hopefully the Mac OS X one is
            not broken!)
          + Include profile name in the GTK2 window name
          + Added bindings ',' (same as '<') and '.' (same as '>') in the
            GTK2 UI
     * Mac GUI:
          + actions like < and > scroll to the next item as necessary.
          + Restart has a menu item and keyboard shortcut (command-R).
          + Added a command-line tool for Mac OS X. It can be installed
            from the Unison menu.
          + New icon.
          + Handle the "help" command-line argument properly.
          + Handle profiles given on the command line properly.
          + When a profile has been selected, the profile dialog is
            replaced by a "connecting" message while the connection is
            being made. This gives better feedback.
          + Size of left and right columns is now large enough so that
            "PropsChanged" is not cut off.
     * Minor changes:
          + Disable multi-threading when both roots are local
          + Improved error handling code. In particular, make sure all
            files are closed in case of a transient failure
          + Under Windows, use $UNISON for home directory as a last
            resort (it was wrongly moved before $HOME and $USERPROFILE in
            Unison 2.12.0)
          + Reopen the logfile if its name changes (profile change)
          + Double-check that permissions and modification times have
            been properly set: there are some combination of OS and
            filesystem on which setting them can fail in a silent way.
          + Check for bad Windows filenames for pure Windows
            synchronization also (not just cross architecture
            synchronization). This way, filenames containing backslashes,
            which are not correctly handled by unison, are rejected right
            away.
          + Attempt to resolve issues with synchronizing modification
            times of read-only files under Windows
          + Ignore chmod failures when deleting files
          + Ignore trailing dots in filenames in case insensitive mode
          + Proper quoting of paths, files and extensions ignored using
            the UI
          + The strings CURRENT1 and CURRENT2 are now correctly
            substitued when they occur in the diff preference
          + Improvements to syncing resource forks between Macs via a
            non-Mac system.

   Changes since 2.10.2:
     * INCOMPATIBLE CHANGE: Archive format has changed.
     * Source code availability: The Unison sources are now managed using
       Subversion. One nice side-effect is that anonymous checkout is now
       possible, like this:
        svn co https://cvs.cis.upenn.edu:3690/svnroot/unison/
       We will also continue to export a "developer tarball" of the
       current (modulo one day) sources in the web export directory. To
       receive commit logs for changes to the sources, subscribe to the
       unison-hackers list
       (http://www.cis.upenn.edu/ bcpierce/unison/lists.html).
     * Text user interface:
          + Substantial reworking of the internal logic of the text UI to
            make it a bit easier to modify.
          + The dumbtty flag in the text UI is automatically set to true
            if the client is running on a Unix system and the EMACS
            environment variable is set to anything other than the empty
            string.
     * Native OS X gui:
          + Added a synchronize menu item with keyboard shortcut
          + Added a merge menu item, still needs to be debugged
          + Fixes to compile for Panther
          + Miscellaneous improvements and bugfixes
     * Small changes:
          + Changed the filename checking code to apply to Windows only,
            instead of OS X as well.
          + Finder flags now synchronized
          + Fallback in copy.ml for filesystem that do not support O_EXCL
          + Changed buffer size for local file copy (was highly
            inefficient with synchronous writes)
          + Ignore chmod failure when deleting a directory
          + Fixed assertion failure when resolving a conflict content
            change / permission changes in favor of the content change.
          + Workaround for transferring large files using rsync.
          + Use buffered I/O for files (this is the only way to open
            files in binary mode under Cygwin).
          + On non-Cygwin Windows systems, the UNISON environment
            variable is now checked first to determine where to look for
            Unison's archive and preference files, followed by HOME and
            USERPROFILE in that order. On Unix and Cygwin systems, HOME
            is used.
          + Generalized diff preference so that it can be given either as
            just the command name to be used for calculating diffs or
            else a whole command line, containing the strings CURRENT1
            and CURRENT2, which will be replaced by the names of the
            files to be diff'ed before the command is called.
          + Recognize password prompts in some newer versions of ssh.

   Changes since 2.9.20:
     * INCOMPATIBLE CHANGE: Archive format has changed.
     * Major functionality changes:
          + Major tidying and enhancement of 'merge' functionality. The
            main user-visible change is that the external merge program
            may either write the merged output to a single new file, as
            before, or it may modify one or both of its input files, or
            it may write two new files. In the latter cases, its
            modifications will be copied back into place on both the
            local and the remote host, and (if the two files are now
            equal) the archive will be updated appropriately. More
            information can be found in the user manual. Thanks to Malo
            Denielou and Alan Schmitt for these improvements.
            Warning: the new merging functionality is not completely
            compatible with old versions! Check the manual for details.
          + Files larger than 2Gb are now supported.
          + Added preliminary (and still somewhat experimental) support
            for the Apple OS X operating system.
               o Resource forks should be transferred correctly. (See the
                 manual for details of how this works when synchronizing
                 HFS with non-HFS volumes.) Synchronization of file type
                 and creator information is also supported.
               o On OSX systems, the name of the directory for storing
                 Unison's archives, preference files, etc., is now
                 determined as follows:
                    # if ~/.unison exists, use it
                    # otherwise, use ~/Library/Application
                      Support/Unison, creating it if necessary.
               o A preliminary native-Cocoa user interface is under
                 construction. This still needs some work, and some users
                 experience unpredictable crashes, so it is only for
                 hackers for now. Run make with UISTYLE=mac to build this
                 interface.
     * Minor functionality changes:
          + Added an ignorelocks preference, which forces Unison to
            override left-over archive locks. (Setting this preference is
            dangerous! Use it only if you are positive you know what you
            are doing.)
          + Running with the -timers flag set to true will now show the
            total time taken to check for updates on each directory.
            (This can be helpful for tidying directories to improve
            update detection times.)
          + Added a new preference assumeContentsAreImmutable. If a
            directory matches one of the patterns set in this preference,
            then update detection is skipped for files in this directory.
            (The purpose is to speed update detection for cases like Mail
            folders, which contain lots and lots of immutable files.)
            Also a preference assumeContentsAreImmutableNot, which
            overrides the first, similarly to ignorenot. (Later
            amendment: these preferences are now called immutable and
            immutablenot.)
          + The ignorecase flag has been changed from a boolean to a
            three-valued preference. The default setting, called default,
            checks the operating systems running on the client and server
            and ignores filename case if either of them is OSX or
            Windows. Setting ignorecase to true or false overrides this
            behavior. If you have been setting ignorecase on the command
            line using -ignorecase=true or -ignorecase=false, you will
            need to change to -ignorecase true or -ignorecase false.
          + a new preference, 'repeat', for the text user interface
            (only). If 'repeat' is set to a number, then, after it
            finishes synchronizing, Unison will wait for that many
            seconds and then start over, continuing this way until it is
            killed from outside. Setting repeat to true will
            automatically set the batch preference to true.
          + Excel files are now handled specially, so that the fastcheck
            optimization is skipped even if the fastcheck flag is set.
            (Excel does some naughty things with modtimes, making this
            optimization unreliable and leading to failures during change
            propagation.)
          + The ignorecase flag has been changed from a boolean to a
            three-valued preference. The default setting, called
            'default', checks the operating systems running on the client
            and server and ignores filename case if either of them is OSX
            or Windows. Setting ignorecase to 'true' or 'false' overrides
            this behavior.
          + Added a new preference, 'repeat', for the text user interface
            (only, at the moment). If 'repeat' is set to a number, then,
            after it finishes synchronizing, Unison will wait for that
            many seconds and then start over, continuing this way until
            it is killed from outside. Setting repeat to true will
            automatically set the batch preference to true.
          + The 'rshargs' preference has been split into 'rshargs' and
            'sshargs' (mainly to make the documentation clearer). In
            fact, 'rshargs' is no longer mentioned in the documentation
            at all, since pretty much everybody uses ssh now anyway.
     * Documentation
          + The web pages have been completely redesigned and
            reorganized. (Thanks to Alan Schmitt for help with this.)
     * User interface improvements
          + Added a GTK2 user interface, capable (among other things) of
            displaying filenames in any locale encoding. Kudos to Stephen
            Tse for contributing this code!
          + The text UI now prints a list of failed and skipped transfers
            at the end of synchronization.
          + Restarting update detection from the graphical UI will reload
            the current profile (which in particular will reset the -path
            preference, in case it has been narrowed by using the
            "Recheck unsynchronized items" command).
          + Several small improvements to the text user interface,
            including a progress display.
     * Bug fixes (too numerous to count, actually, but here are some):
          + The maxthreads preference works now.
          + Fixed bug where warning message about uname returning an
            unrecognized result was preventing connection to server. (The
            warning is no longer printed, and all systems where 'uname'
            returns anything other than 'Darwin' are assumed not to be
            running OS X.)
          + Fixed a problem on OS X that caused some valid file names
            (e.g., those including colons) to be considered invalid.
          + Patched Path.followLink to follow links under cygwin in
            addition to Unix (suggested by Matt Swift).
          + Small change to the storeRootsName function, suggested by
            bliviero at ichips.intel.com, to fix a problem in unison with
            the `rootalias' option, which allows you to tell unison that
            two roots contain the same files. Rootalias was being applied
            after the hosts were sorted, so it wouldn't work properly in
            all cases.
          + Incorporated a fix by Dmitry Bely for setting utimes of
            read-only files on Win32 systems.
     * Installation / portability:
          + Unison now compiles with OCaml version 3.07 and later out of
            the box.
          + Makefile.OCaml fixed to compile out of the box under OpenBSD.
          + a few additional ports (e.g. OpenBSD, Zaurus/IPAQ) are now
            mentioned in the documentation
          + Unison can now be installed easily on OSX systems using the
            Fink package manager

   Changes since 2.9.1:
     * Added a preference maxthreads that can be used to limit the number
       of simultaneous file transfers.
     * Added a backupdir preference, which controls where backup files
       are stored.
     * Basic support added for OSX. In particular, Unison now recognizes
       when one of the hosts being synchronized is running OSX and
       switches to a case-insensitive treatment of filenames (i.e., 'foo'
       and 'FOO' are considered to be the same file). (OSX is not yet
       fully working, however: in particular, files with resource forks
       will not be synchronized correctly.)
     * The same hash used to form the archive name is now also added to
       the names of the temp files created during file transfer. The
       reason for this is that, during update detection, we are going to
       silently delete any old temp files that we find along the way, and
       we want to prevent ourselves from deleting temp files belonging to
       other instances of Unison that may be running in parallel, e.g.
       synchronizing with a different host. Thanks to Ruslan Ermilov for
       this suggestion.
     * Several small user interface improvements
     * Documentation
          + FAQ and bug reporting instructions have been split out as
            separate HTML pages, accessible directly from the unison web
            page.
          + Additions to FAQ, in particular suggestions about performance
            tuning.
     * Makefile
          + Makefile.OCaml now sets UISTYLE=text or UISTYLE=gtk
            automatically, depending on whether it finds lablgtk
            installed
          + Unison should now compile "out of the box" under OSX

   Changes since 2.8.1:
     * Changing profile works again under Windows
     * File movement optimization: Unison now tries to use local copy
       instead of transfer for moved or copied files. It is controled by
       a boolean option "xferbycopying".
     * Network statistics window (transfer rate, amount of data
       transferred). [NB: not available in Windows-Cygwin version.]
     * symlinks work under the cygwin version (which is dynamically
       linked).
     * Fixed potential deadlock when synchronizing between Windows and
       Unix
     * Small improvements:
          + If neither the
            tt USERPROFILE nor the
            tt HOME environment variables are set, then Unison will put
            its temporary commit log (called
            tt DANGER.README) into the directory named by the
            tt UNISON environment variable, if any; otherwise it will use
            tt C:.
          + alternative set of values for fastcheck: yes = true; no =
            false; default = auto.
          + -silent implies -contactquietly
     * Source code:
          + Code reorganization and tidying. (Started breaking up some of
            the basic utility modules so that the non-unison-specific
            stuff can be made available for other projects.)
          + several Makefile and docs changes (for release);
          + further comments in "update.ml";
          + connection information is not stored in global variables
            anymore.

   Changes since 2.7.78:
     * Small bugfix to textual user interface under Unix (to avoid
       leaving the terminal in a bad state where it would not echo inputs
       after Unison exited).

   Changes since 2.7.39:
     * Improvements to the main web page (stable and beta version docs
       are now both accessible).
     * User manual revised.
     * Added some new preferences:
          + "sshcmd" and "rshcmd" for specifying paths to ssh and rsh
            programs.
          + "contactquietly" for suppressing the "contacting server"
            message during Unison startup (under the graphical UI).
     * Bug fixes:
          + Fixed small bug in UI that neglected to change the displayed
            column headers if loading a new profile caused the roots to
            change.
          + Fixed a bug that would put the text UI into an infinite loop
            if it encountered a conflict when run in batch mode.
          + Added some code to try to fix the display of non-Ascii
            characters in filenames on Windows systems in the GTK UI.
            (This code is currently untested--if you're one of the people
            that had reported problems with display of non-ascii
            filenames, we'd appreciate knowing if this actually fixes
            things.)
          + `-prefer/-force newer' works properly now. (The bug was
            reported by Sebastian Urbaniak and Sean Fulton.)
     * User interface and Unison behavior:
          + Renamed `Proceed' to `Go' in the graphical UI.
          + Added exit status for the textual user interface.
          + Paths that are not synchronized because of conflicts or
            errors during update detection are now noted in the log file.
          + [END] messages in log now use a briefer format
          + Changed the text UI startup sequence so that
            tt ./unison -ui text will use the default profile instead of
            failing.
          + Made some improvements to the error messages.
          + Added some debugging messages to remote.ml.

   Changes since 2.7.7:
     * Incorporated, once again, a multi-threaded transport sub-system.
       It transfers several files at the same time, thereby making much
       more effective use of available network bandwidth. Unlike the
       earlier attempt, this time we do not rely on the native thread
       library of OCaml. Instead, we implement a light-weight,
       non-preemptive multi-thread library in OCaml directly. This
       version appears stable.
       Some adjustments to unison are made to accommodate the
       multi-threaded version. These include, in particular, changes to
       the user interface and logging, for example:
          + Two log entries for each transferring task, one for the
            beginning, one for the end.
          + Suppressed warning messages against removing temp files left
            by a previous unison run, because warning does not work
            nicely under multi-threading. The temp file names are made
            less likely to coincide with the name of a file created by
            the user. They take the form
            .#<filename>.<serial>.unison.tmp. [N.b. This was later
            changed to .unison.<filename>.<serial>.unison.tmp.]
     * Added a new command to the GTK user interface: pressing 'f' causes
       Unison to start a new update detection phase, using as paths just
       those paths that have been detected as changed and not yet marked
       as successfully completed. Use this command to quickly restart
       Unison on just the set of paths still needing attention after a
       previous run.
     * Made the ignorecase preference user-visible, and changed the
       initialization code so that it can be manually set to true, even
       if neither host is running Windows. (This may be useful, e.g.,
       when using Unison running on a Unix system with a FAT volume
       mounted.)
     * Small improvements and bug fixes:
          + Errors in preference files now generate fatal errors rather
            than warnings at startup time. (I.e., you can't go on from
            them.) Also, we fixed a bug that was preventing these
            warnings from appearing in the text UI, so some users who
            have been running (unsuspectingly) with garbage in their
            prefs files may now get error reports.
          + Error reporting for preference files now provides file name
            and line number.
          + More intelligible message in the case of identical change to
            the same files: "Nothing to do: replicas have been changed
            only in identical ways since last sync."
          + Files with prefix '.#' excluded when scanning for preference
            files.
          + Rsync instructions are send directly instead of first
            marshaled.
          + Won't try forever to get the fingerprint of a continuously
            changing file: unison will give up after certain number of
            retries.
          + Other bug fixes, including the one reported by Peter Selinger
            (force=older preference not working).
     * Compilation:
          + Upgraded to the new OCaml 3.04 compiler, with the LablGtk
            1.2.3 library (patched version used for compiling under
            Windows).
          + Added the option to compile unison on the Windows platform
            with Cygwin GNU C compiler. This option only supports
            building dynamically linked unison executables.

   Changes since 2.7.4:
     * Fixed a silly (but debilitating) bug in the client startup
       sequence.

   Changes since 2.7.1:
     * Added addprefsto preference, which (when set) controls which
       preference file new preferences (e.g. new ignore patterns) are
       added to.
     * Bug fix: read the initial connection header one byte at a time, so
       that we don't block if the header is shorter than expected. (This
       bug did not affect normal operation -- it just made it hard to
       tell when you were trying to use Unison incorrectly with an old
       version of the server, since it would hang instead of giving an
       error message.)

   Changes since 2.6.59:
     * Changed fastcheck from a boolean to a string preference. Its legal
       values are yes (for a fast check), no (for a safe check), or
       default (for a fast check--which also happens to be safe--when
       running on Unix and a safe check when on Windows). The default is
       default.
     * Several preferences have been renamed for consistency. All
       preference names are now spelled out in lowercase. For backward
       compatibility, the old names still work, but they are not
       mentioned in the manual any more.
     * The temp files created by the 'diff' and 'merge' commands are now
       named by prepending a new prefix to the file name, rather than
       appending a suffix. This should avoid confusing diff/merge
       programs that depend on the suffix to guess the type of the file
       contents.
     * We now set the keepalive option on the server socket, to make sure
       that the server times out if the communication link is
       unexpectedly broken.
     * Bug fixes:
          + When updating small files, Unison now closes the destination
            file.
          + File permissions are properly updated when the file is behind
            a followed link.
          + Several other small fixes.

   Changes since 2.6.38:
     * Major Windows performance improvement!
       We've added a preference fastcheck that makes Unison look only at
       a file's creation time and last-modified time to check whether it
       has changed. This should result in a huge speedup when checking
       for updates in large replicas.
       When this switch is set, Unison will use file creation times as
       'pseudo inode numbers' when scanning Windows replicas for updates,
       instead of reading the full contents of every file. This may cause
       Unison to miss propagating an update if the create time,
       modification time, and length of the file are all unchanged by the
       update (this is not easy to achieve, but it can be done). However,
       Unison will never overwrite such an update with a change from the
       other replica, since it always does a safe check for updates just
       before propagating a change. Thus, it is reasonable to use this
       switch most of the time and occasionally run Unison once with
       fastcheck set to false, if you are worried that Unison may have
       overlooked an update.
       Warning: This change is has not yet been thoroughly field-tested.
       If you set the fastcheck preference, pay careful attention to what
       Unison is doing.
     * New functionality: centralized backups and merging
          + This version incorporates two pieces of major new
            functionality, implemented by Sylvain Roy during a summer
            internship at Penn: a centralized backup facility that keeps
            a full backup of (selected files in) each replica, and a
            merging feature that allows Unison to invoke an external
            file-merging tool to resolve conflicting changes to
            individual files.
          + Centralized backups:
               o Unison now maintains full backups of the
                 last-synchronized versions of (some of) the files in
                 each replica; these function both as backups in the
                 usual sense and as the "common version" when invoking
                 external merge programs.
               o The backed up files are stored in a directory
                 /.unison/backup on each host. (The name of this
                 directory can be changed by setting the environment
                 variable UNISONBACKUPDIR.)
               o The predicate backup controls which files are actually
                 backed up: giving the preference 'backup = Path *'
                 causes backing up of all files.
               o Files are added to the backup directory whenever unison
                 updates its archive. This means that
                    # When unison reconstructs its archive from scratch
                      (e.g., because of an upgrade, or because the
                      archive files have been manually deleted), all
                      files will be backed up.
                    # Otherwise, each file will be backed up the first
                      time unison propagates an update for it.
               o The preference backupversions controls how many previous
                 versions of each file are kept. The default is 2 (i.e.,
                 the last synchronized version plus one backup).
               o For backward compatibility, the backups preference is
                 also still supported, but backup is now preferred.
               o It is OK to manually delete files from the backup
                 directory (or to throw away the directory itself).
                 Before unison uses any of these files for anything
                 important, it checks that its fingerprint matches the
                 one that it expects.
          + Merging:
               o Both user interfaces offer a new 'merge' command,
                 invoked by pressing 'm' (with a changed file selected).
               o The actual merging is performed by an external program.
                 The preferences merge and merge2 control how this
                 program is invoked. If a backup exists for this file
                 (see the backup preference), then the merge preference
                 is used for this purpose; otherwise merge2 is used. In
                 both cases, the value of the preference should be a
                 string representing the command that should be passed to
                 a shell to invoke the merge program. Within this string,
                 the special substrings CURRENT1, CURRENT2, NEW, and OLD
                 may appear at any point. Unison will substitute these as
                 follows before invoking the command:
                    # CURRENT1 is replaced by the name of the local copy
                      of the file;
                    # CURRENT2 is replaced by the name of a temporary
                      file, into which the contents of the remote copy of
                      the file have been transferred by Unison prior to
                      performing the merge;
                    # NEW is replaced by the name of a temporary file
                      that Unison expects to be written by the merge
                      program when it finishes, giving the desired new
                      contents of the file; and
                    # OLD is replaced by the name of the backed up copy
                      of the original version of the file (i.e., its
                      state at the end of the last successful run of
                      Unison), if one exists (applies only to merge, not
                      merge2).
                 For example, on Unix systems setting the merge
                 preference to
   merge = diff3 -m CURRENT1 OLD CURRENT2 > NEW
                 will tell Unison to use the external diff3 program for
                 merging.
                 A large number of external merging programs are
                 available. For example, emacs users may find the
                 following convenient:
    merge2 = emacs -q --eval '(ediff-merge-files "CURRENT1" "CURRENT2"
               nil "NEW")'
    merge = emacs -q --eval '(ediff-merge-files-with-ancestor
               "CURRENT1" "CURRENT2" "OLD" nil "NEW")'
                 (These commands are displayed here on two lines to avoid
                 running off the edge of the page. In your preference
                 file, each should be written on a single line.)
               o If the external program exits without leaving any file
                 at the path NEW, Unison considers the merge to have
                 failed. If the merge program writes a file called NEW
                 but exits with a non-zero status code, then Unison
                 considers the merge to have succeeded but to have
                 generated conflicts. In this case, it attempts to invoke
                 an external editor so that the user can resolve the
                 conflicts. The value of the editor preference controls
                 what editor is invoked by Unison. The default is emacs.
               o Please send us suggestions for other useful values of
                 the merge2 and merge preferences - we'd like to give
                 several examples in the manual.
     * Smaller changes:
          + When one preference file includes another, unison no longer
            adds the suffix '.prf' to the included file by default. If a
            file with precisely the given name exists in the .unison
            directory, it will be used; otherwise Unison will add .prf,
            as it did before. (This change means that included preference
            files can be named blah.include instead of blah.prf, so that
            unison will not offer them in its 'choose a preference file'
            dialog.)
          + For Linux systems, we now offer both a statically linked and
            a dynamically linked executable. The static one is larger,
            but will probably run on more systems, since it doesn't
            depend on the same versions of dynamically linked library
            modules being available.
          + Fixed the force and prefer preferences, which were getting
            the propagation direction exactly backwards.
          + Fixed a bug in the startup code that would cause unison to
            crash when the default profile (~/.unison/default.prf) does
            not exist.
          + Fixed a bug where, on the run when a profile is first
            created, Unison would confusingly display the roots in
            reverse order in the user interface.
     * For developers:
          + We've added a module dependency diagram to the source
            distribution, in src/DEPENDENCIES.ps, to help new prospective
            developers with navigating the code.

   Changes since 2.6.11:
     * INCOMPATIBLE CHANGE: Archive format has changed.
     * INCOMPATIBLE CHANGE: The startup sequence has been completely
       rewritten and greatly simplified. The main user-visible change is
       that the defaultpath preference has been removed. Its effect can
       be approximated by using multiple profiles, with include
       directives to incorporate common settings. All uses of defaultpath
       in existing profiles should be changed to path.
       Another change in startup behavior that will affect some users is
       that it is no longer possible to specify roots both in the profile
       and on the command line.
       You can achieve a similar effect, though, by breaking your profile
       into two:

  default.prf =
      root = blah
      root = foo
      include common

  common.prf =
      <everything else>
       Now do
  unison common root1 root2
       when you want to specify roots explicitly.
     * The -prefer and -force options have been extended to allow users
       to specify that files with more recent modtimes should be
       propagated, writing either -prefer newer or -force newer. (For
       symmetry, Unison will also accept -prefer older or -force older.)
       The -force older/newer options can only be used when -times is
       also set.
       The graphical user interface provides access to these facilities
       on a one-off basis via the Actions menu.
     * Names of roots can now be "aliased" to allow replicas to be
       relocated without changing the name of the archive file where
       Unison stores information between runs. (This feature is for
       experts only. See the "Archive Files" section of the manual for
       more information.)
     * Graphical user-interface:
          + A new command is provided in the Synchronization menu for
            switching to a new profile without restarting Unison from
            scratch.
          + The GUI also supports one-key shortcuts for commonly used
            profiles. If a profile contains a preference of the form 'key
            = n', where n is a single digit, then pressing this key will
            cause Unison to immediately switch to this profile and begin
            synchronization again from scratch. (Any actions that may
            have been selected for a set of changes currently being
            displayed will be discarded.)
          + Each profile may include a preference 'label = <string>'
            giving a descriptive string that described the options
            selected in this profile. The string is listed along with the
            profile name in the profile selection dialog, and displayed
            in the top-right corner of the main Unison window.
     * Minor:
          + Fixed a bug that would sometimes cause the 'diff' display to
            order the files backwards relative to the main user
            interface. (Thanks to Pascal Brisset for this fix.)
          + On Unix systems, the graphical version of Unison will check
            the DISPLAY variable and, if it is not set, automatically
            fall back to the textual user interface.
          + Synchronization paths (path preferences) are now matched
            against the ignore preferences. So if a path is both
            specified in a path preference and ignored, it will be
            skipped.
          + Numerous other bugfixes and small improvements.

   Changes since 2.6.1:
     * The synchronization of modification times has been disabled for
       directories.
     * Preference files may now include lines of the form include <name>,
       which will cause name.prf to be read at that point.
     * The synchronization of permission between Windows and Unix now
       works properly.
     * A binding CYGWIN=binmode in now added to the environment so that
       the Cygwin port of OpenSSH works properly in a non-Cygwin context.
     * The servercmd and addversionno preferences can now be used
       together: -addversionno appends an appropriate -NNN to the server
       command, which is found by using the value of the -servercmd
       preference if there is one, or else just unison.
     * Both '-pref=val' and '-pref val' are now allowed for boolean
       values. (The former can be used to set a preference to false.)
     * Lot of small bugs fixed.

   Changes since 2.5.31:
     * The log preference is now set to true by default, since the log
       file seems useful for most users.
     * Several miscellaneous bugfixes (most involving symlinks).

   Changes since 2.5.25:
     * INCOMPATIBLE CHANGE: Archive format has changed (again).
     * Several significant bugs introduced in 2.5.25 have been fixed.

   Changes since 2.5.1:
     * INCOMPATIBLE CHANGE: Archive format has changed. Make sure you
       synchronize your replicas before upgrading, to avoid spurious
       conflicts. The first sync after upgrading will be slow.
     * New functionality:
          + Unison now synchronizes file modtimes, user-ids, and
            group-ids.
            These new features are controlled by a set of new
            preferences, all of which are currently false by default.
               o When the times preference is set to true, file
                 modification times are propaged. (Because the
                 representations of time may not have the same
                 granularity on both replicas, Unison may not always be
                 able to make the modtimes precisely equal, but it will
                 get them as close as the operating systems involved
                 allow.)
               o When the owner preference is set to true, file ownership
                 information is synchronized.
               o When the group preference is set to true, group
                 information is synchronized.
               o When the numericIds preference is set to true, owner and
                 group information is synchronized numerically. By
                 default, owner and group numbers are converted to names
                 on each replica and these names are synchronized. (The
                 special user id 0 and the special group 0 are never
                 mapped via user/group names even if this preference is
                 not set.)
          + Added an integer-valued preference perms that can be used to
            control the propagation of permission bits. The value of this
            preference is a mask indicating which permission bits should
            be synchronized. It is set by default to 0o1777: all bits but
            the set-uid and set-gid bits are synchronised (synchronizing
            theses latter bits can be a security hazard). If you want to
            synchronize all bits, you can set the value of this
            preference to -1.
          + Added a log preference (default false), which makes Unison
            keep a complete record of the changes it makes to the
            replicas. By default, this record is written to a file called
            unison.log in the user's home directory (the value of the
            HOME environment variable). If you want it someplace else,
            set the logfile preference to the full pathname you want
            Unison to use.
          + Added an ignorenot preference that maintains a set of
            patterns for paths that should definitely not be ignored,
            whether or not they match an ignore pattern. (That is, a path
            will now be ignored iff it matches an ignore pattern and does
            not match any ignorenot patterns.)
     * User-interface improvements:
          + Roots are now displayed in the user interface in the same
            order as they were given on the command line or in the
            preferences file.
          + When the batch preference is set, the graphical user
            interface no longer waits for user confirmation when it
            displays a warning message: it simply pops up an advisory
            window with a Dismiss button at the bottom and keeps on
            going.
          + Added a new preference for controlling how many status
            messages are printed during update detection: statusdepth
            controls the maximum depth for paths on the local machine
            (longer paths are not displayed, nor are non-directory
            paths). The value should be an integer; default is 1.
          + Removed the trace and silent preferences. They did not seem
            very useful, and there were too many preferences for
            controlling output in various ways.
          + The text UI now displays just the default command (the one
            that will be used if the user just types <return>) instead of
            all available commands. Typing ? will print the full list of
            possibilities.
          + The function that finds the canonical hostname of the local
            host (which is used, for example, in calculating the name of
            the archive file used to remember which files have been
            synchronized) normally uses the gethostname operating system
            call. However, if the environment variable
            UNISONLOCALHOSTNAME is set, its value will now be used
            instead. This makes it easier to use Unison in situations
            where a machine's name changes frequently (e.g., because it
            is a laptop and gets moved around a lot).
          + File owner and group are now displayed in the "detail window"
            at the bottom of the screen, when unison is configured to
            synchronize them.
     * For hackers:
          + Updated to Jacques Garrigue's new version of lablgtk, which
            means we can throw away our local patched version.
            If you're compiling the GTK version of unison from sources,
            you'll need to update your copy of lablgtk to the developers
            release. (Warning: installing lablgtk under Windows is
            currently a bit challenging.)
          + The TODO.txt file (in the source distribution) has been
            cleaned up and reorganized. The list of pending tasks should
            be much easier to make sense of, for people that may want to
            contribute their programming energies. There is also a
            separate file BUGS.txt for open bugs.
          + The Tk user interface has been removed (it was not being
            maintained and no longer compiles).
          + The debug preference now prints quite a bit of additional
            information that should be useful for identifying sources of
            problems.
          + The version number of the remote server is now checked right
            away during the connection setup handshake, rather than
            later. (Somebody sent a bug report of a server crash that
            turned out to come from using inconsistent versions: better
            to check this earlier and in a way that can't crash either
            client or server.)
          + Unison now runs correctly on 64-bit architectures (e.g. Alpha
            linux). We will not be distributing binaries for these
            architectures ourselves (at least for a while) but if someone
            would like to make them available, we'll be glad to provide a
            link to them.
     * Bug fixes:
          + Pattern matching (e.g. for ignore) is now case-insensitive
            when Unison is in case-insensitive mode (i.e., when one of
            the replicas is on a windows machine).
          + Some people had trouble with mysterious failures during
            propagation of updates, where files would be falsely reported
            as having changed during synchronization. This should be
            fixed.
          + Numerous smaller fixes.

   Changes since 2.4.1:
     * Added a number of 'sorting modes' for the user interface. By
       default, conflicting changes are displayed at the top, and the
       rest of the entries are sorted in alphabetical order. This
       behavior can be changed in the following ways:
          + Setting the sortnewfirst preference to true causes newly
            created files to be displayed before changed files.
          + Setting sortbysize causes files to be displayed in increasing
            order of size.
          + Giving the preference sortfirst=<pattern> (where <pattern> is
            a path descriptor in the same format as 'ignore' and 'follow'
            patterns, causes paths matching this pattern to be displayed
            first.
          + Similarly, giving the preference sortlast=<pattern> causes
            paths matching this pattern to be displayed last.
       The sorting preferences are described in more detail in the user
       manual. The sortnewfirst and sortbysize flags can also be accessed
       from the 'Sort' menu in the grpahical user interface.
     * Added two new preferences that can be used to change unison's
       fundamental behavior to make it more like a mirroring tool instead
       of a synchronizer.
          + Giving the preference prefer with argument <root> (by adding
            -prefer <root> to the command line or prefer=<root>) to your
            profile) means that, if there is a conflict, the contents of
            <root> should be propagated to the other replica (with no
            questions asked). Non-conflicting changes are treated as
            usual.
          + Giving the preference force with argument <root> will make
            unison resolve all differences in favor of the given root,
            even if it was the other replica that was changed.
       These options should be used with care! (More information is
       available in the manual.)
     * Small changes:
          + Changed default answer to 'Yes' in all two-button dialogs in
            the graphical interface (this seems more intuitive).
          + The rsync preference has been removed (it was used to
            activate rsync compression for file transfers, but rsync
            compression is now enabled by default).
          + In the text user interface, the arrows indicating which
            direction changes are being propagated are printed
            differently when the user has overridded Unison's default
            recommendation (====> instead of ---->). This matches the
            behavior of the graphical interface, which displays such
            arrows in a different color.
          + Carriage returns (Control-M's) are ignored at the ends of
            lines in profiles, for Windows compatibility.
          + All preferences are now fully documented in the user manual.

   Changes since 2.3.12:
     * INCOMPATIBLE CHANGE: Archive format has changed. Make sure you
       synchronize your replicas before upgrading, to avoid spurious
       conflicts. The first sync after upgrading will be slow.
     * New/improved functionality:
          + A new preference -sortbysize controls the order in which
            changes are displayed to the user: when it is set to true,
            the smallest changed files are displayed first. (The default
            setting is false.)
          + A new preference -sortnewfirst causes newly created files to
            be listed before other updates in the user interface.
          + We now allow the ssh protocol to specify a port.
          + Incompatible change: The unison: protocol is deprecated, and
            we added file: and socket:. You may have to modify your
            profiles in the .unison directory. If a replica is specified
            without an explicit protocol, we now assume it refers to a
            file. (Previously "//saul/foo" meant to use SSH to connect to
            saul, then access the foo directory. Now it means to access
            saul via a remote file mechanism such as samba; the old
            effect is now achieved by writing ssh://saul/foo.)
          + Changed the startup sequence for the case where roots are
            given but no profile is given on the command line. The new
            behavior is to use the default profile (creating it if it
            does not exist), and temporarily override its roots. The
            manual claimed that this case would work by reading no
            profile at all, but AFAIK this was never true.
          + In all user interfaces, files with conflicts are always
            listed first
          + A new preference 'sshversion' can be used to control which
            version of ssh should be used to connect to the server. Legal
            values are 1 and 2. (Default is empty, which will make unison
            use whatever version of ssh is installed as the default 'ssh'
            command.)
          + The situation when the permissions of a file was updated the
            same on both side is now handled correctly (we used to report
            a spurious conflict)
     * Improvements for the Windows version:
          + The fact that filenames are treated case-insensitively under
            Windows should now be handled correctly. The exact behavior
            is described in the cross-platform section of the manual.
          + It should be possible to synchronize with Windows shares,
            e.g., //host/drive/path.
          + Workarounds to the bug in syncing root directories in
            Windows. The most difficult thing to fix is an ocaml bug:
            Unix.opendir fails on c: in some versions of Windows.
     * Improvements to the GTK user interface (the Tk interface is no
       longer being maintained):
          + The UI now displays actions differently (in blue) when they
            have been explicitly changed by the user from Unison's
            default recommendation.
          + More colorful appearance.
          + The initial profile selection window works better.
          + If any transfers failed, a message to this effect is
            displayed along with 'Synchronization complete' at the end of
            the transfer phase (in case they may have scrolled off the
            top).
          + Added a global progress meter, displaying the percentage of
            total bytes that have been transferred so far.
     * Improvements to the text user interface:
          + The file details will be displayed automatically when a
            conflict is been detected.
          + when a warning is generated (e.g. for a temporary file left
            over from a previous run of unison) Unison will no longer
            wait for a response if it is running in -batch mode.
          + The UI now displays a short list of possible inputs each time
            it waits for user interaction.
          + The UI now quits immediately (rather than looping back and
            starting the interaction again) if the user presses 'q' when
            asked whether to propagate changes.
          + Pressing 'g' in the text user interface will proceed
            immediately with propagating updates, without asking any more
            questions.
     * Documentation and installation changes:
          + The manual now includes a FAQ, plus sections on common
            problems and on tricks contributed by users.
          + Both the download page and the download directory explicitly
            say what are the current stable and beta-test version
            numbers.
          + The OCaml sources for the up-to-the-minute developers'
            version (not guaranteed to be stable, or even to compile, at
            any given time!) are now available from the download page.
          + Added a subsection to the manual describing cross-platform
            issues (case conflicts, illegal filenames)
     * Many small bug fixes and random improvements.

   Changes since 2.3.1:
     * Several bug fixes. The most important is a bug in the rsync module
       that would occasionally cause change propagation to fail with a
       'rename' error.

   Changes since 2.2:
     * The multi-threaded transport system is now disabled by default.
       (It is not stable enough yet.)
     * Various bug fixes.
     * A new experimental feature:
       The final component of a -path argument may now be the wildcard
       specifier *. When Unison sees such a path, it expands this path on
       the client into into the corresponding list of paths by listing
       the contents of that directory.
       Note that if you use wildcard paths from the command line, you
       will probably need to use quotes or a backslash to prevent the *
       from being interpreted by your shell.
       If both roots are local, the contents of the first one will be
       used for expanding wildcard paths. (Nb: this is the first one
       after the canonization step - i.e., the one that is listed first
       in the user interface - not the one listed first on the command
       line or in the preferences file.)

   Changes since 2.1:
     * The transport subsystem now includes an implementation by Sylvain
       Gommier and Norman Ramsey of Tridgell and Mackerras's rsync
       protocol. This protocol achieves much faster transfers when only a
       small part of a large file has been changed by sending just diffs.
       This feature is mainly helpful for transfers over slow links--on
       fast local area networks it can actually degrade performance--so
       we have left it off by default. Start unison with the -rsync
       option (or put rsync=true in your preferences file) to turn it on.
     * "Progress bars" are now diplayed during remote file transfers,
       showing what percentage of each file has been transferred so far.
     * The version numbering scheme has changed. New releases will now be
       have numbers like 2.2.30, where the second component is
       incremented on every significant public release and the third
       component is the "patch level."
     * Miscellaneous improvements to the GTK-based user interface.
     * The manual is now available in PDF format.
     * We are experimenting with using a multi-threaded transport
       subsystem to transfer several files at the same time, making much
       more effective use of available network bandwidth. This feature is
       not completely stable yet, so by default it is disabled in the
       release version of Unison.
       If you want to play with the multi-threaded version, you'll need
       to recompile Unison from sources (as described in the
       documentation), setting the THREADS flag in Makefile.OCaml to
       true. Make sure that your OCaml compiler has been installed with
       the -with-pthreads configuration option. (You can verify this by
       checking whether the file threads/threads.cma in the OCaml
       standard library directory contains the string -lpthread near the
       end.)

   Changes since 1.292:
     * Reduced memory footprint (this is especially important during the
       first run of unison, where it has to gather information about all
       the files in both repositories).
     * Fixed a bug that would cause the socket server under NT to fail
       after the client exits.
     * Added a SHIFT modifier to the Ignore menu shortcut keys in GTK
       interface (to avoid hitting them accidentally).

   Changes since 1.231:
     * Tunneling over ssh is now supported in the Windows version. See
       the installation section of the manual for detailed instructions.
     * The transport subsystem now includes an implementation of the
       rsync protocol, built by Sylvain Gommier and Norman Ramsey. This
       protocol achieves much faster transfers when only a small part of
       a large file has been changed by sending just diffs. The rsync
       feature is off by default in the current version. Use the -rsync
       switch to turn it on. (Nb. We still have a lot of tuning to do:
       you may not notice much speedup yet.)
     * We're experimenting with a multi-threaded transport subsystem,
       written by Jerome Vouillon. The downloadable binaries are still
       single-threaded: if you want to try the multi-threaded version,
       you'll need to recompile from sources. (Say make THREADS=true.)
       Native thread support from the compiler is required. Use the
       option -threads N to select the maximal number of concurrent
       threads (default is 5). Multi-threaded and single-threaded
       clients/servers can interoperate.
     * A new GTK-based user interface is now available, thanks to Jacques
       Garrigue. The Tk user interface still works, but we'll be shifting
       development effort to the GTK interface from now on.
     * OCaml 3.00 is now required for compiling Unison from sources. The
       modules uitk and myfileselect have been changed to use labltk
       instead of camltk. To compile the Tk interface in Windows, you
       must have ocaml-3.00 and tk8.3. When installing tk8.3, put it in
       c:\Tcl rather than the suggested c:\Program Files\Tcl, and be sure
       to install the headers and libraries (which are not installed by
       default).
     * Added a new -addversionno switch, which causes unison to use
       unison-<currentversionnumber> instead of just unison as the remote
       server command. This allows multiple versions of unison to coexist
       conveniently on the same server: whichever version is run on the
       client, the same version will be selected on the server.

   Changes since 1.219:
     * INCOMPATIBLE CHANGE: Archive format has changed. Make sure you
       synchronize your replicas before upgrading, to avoid spurious
       conflicts. The first sync after upgrading will be slow.
     * This version fixes several annoying bugs, including:
          + Some cases where propagation of file permissions was not
            working.
          + umask is now ignored when creating directories
          + directories are create writable, so that a read-only
            directory and its contents can be propagated.
          + Handling of warnings generated by the server.
          + Synchronizing a path whose parent is not a directory on both
            sides is now flagged as erroneous.
          + Fixed some bugs related to symnbolic links and nonexistant
            roots.
               o When a change (deletion or new contents) is propagated
                 onto a 'follow'ed symlink, the file pointed to by the
                 link is now changed. (We used to change the link itself,
                 which doesn't fit our assertion that 'follow' means the
                 link is completely invisible)
               o When one root did not exist, propagating the other root
                 on top of it used to fail, becuase unison could not
                 calculate the working directory into which to write
                 changes. This should be fixed.
     * A human-readable timestamp has been added to Unison's archive
       files.
     * The semantics of Path and Name regular expressions now correspond
       better.
     * Some minor improvements to the text UI (e.g. a command for going
       back to previous items)
     * The organization of the export directory has changed -- should be
       easier to find / download things now.

   Changes since 1.200:
     * INCOMPATIBLE CHANGE: Archive format has changed. Make sure you
       synchronize your replicas before upgrading, to avoid spurious
       conflicts. The first sync after upgrading will be slow.
     * This version has not been tested extensively on Windows.
     * Major internal changes designed to make unison safer to run at the
       same time as the replicas are being changed by the user.
     * Internal performance improvements.

   Changes since 1.190:
     * INCOMPATIBLE CHANGE: Archive format has changed. Make sure you
       synchronize your replicas before upgrading, to avoid spurious
       conflicts. The first sync after upgrading will be slow.
     * A number of internal functions have been changed to reduce the
       amount of memory allocation, especially during the first
       synchronization. This should help power users with very big
       replicas.
     * Reimplementation of low-level remote procedure call stuff, in
       preparation for adding rsync-like smart file transfer in a later
       release.
     * Miscellaneous bug fixes.

   Changes since 1.180:
     * INCOMPATIBLE CHANGE: Archive format has changed. Make sure you
       synchronize your replicas before upgrading, to avoid spurious
       conflicts. The first sync after upgrading will be slow.
     * Fixed some small bugs in the interpretation of ignore patterns.
     * Fixed some problems that were preventing the Windows version from
       working correctly when click-started.
     * Fixes to treatment of file permissions under Windows, which were
       causing spurious reports of different permissions when
       synchronizing between windows and unix systems.
     * Fixed one more non-tail-recursive list processing function, which
       was causing stack overflows when synchronizing very large
       replicas.

   Changes since 1.169:
     * The text user interface now provides commands for ignoring files.
     * We found and fixed some more non-tail-recursive list processing
       functions. Some power users have reported success with very large
       replicas.
     * INCOMPATIBLE CHANGE: Files ending in .tmp are no longer ignored
       automatically. If you want to ignore such files, put an
       appropriate ignore pattern in your profile.
     * INCOMPATIBLE CHANGE: The syntax of ignore and follow patterns has
       changed. Instead of putting a line of the form
                 ignore = <regexp>
       in your profile (.unison/default.prf), you should put:
                 ignore = Regexp <regexp>
       Moreover, two other styles of pattern are also recognized:
                 ignore = Name <name>
       matches any path in which one component matches <name>, while
                 ignore = Path <path>
       matches exactly the path <path>.
       Standard "globbing" conventions can be used in <name> and <path>:
          + a ? matches any single character except /
          + a * matches any sequence of characters not including /
          + [xyz] matches any character from the set {x, y, z }
          + {a,bb,ccc} matches any one of a, bb, or ccc.
       See the user manual for some examples.

   Changes since 1.146:
     * Some users were reporting stack overflows when synchronizing huge
       directories. We found and fixed some non-tail-recursive list
       processing functions, which we hope will solve the problem. Please
       give it a try and let us know.
     * Major additions to the documentation.

   Changes since 1.142:
     * Major internal tidying and many small bugfixes.
     * Major additions to the user manual.
     * Unison can now be started with no arguments - it will prompt
       automatically for the name of a profile file containing the roots
       to be synchronized. This makes it possible to start the graphical
       UI from a desktop icon.
     * Fixed a small bug where the text UI on NT was raising a 'no such
       signal' exception.

   Changes since 1.139:
     * The precompiled windows binary in the last release was compiled
       with an old OCaml compiler, causing propagation of permissions not
       to work (and perhaps leading to some other strange behaviors we've
       heard reports about). This has been corrected. If you're using
       precompiled binaries on Windows, please upgrade.
     * Added a -debug command line flag, which controls debugging of
       various modules. Say -debug XXX to enable debug tracing for module
       XXX, or -debug all to turn on absolutely everything.
     * Fixed a small bug where the text UI on NT was raising a 'no such
       signal' exception.

   Changes since 1.111:
     * INCOMPATIBLE CHANGE: The names and formats of the preference files
       in the .unison directory have changed. In particular:
          + the file "prefs" should be renamed to default.prf
          + the contents of the file "ignore" should be merged into
            default.prf. Each line of the form REGEXP in ignore should
            become a line of the form ignore = REGEXP in default.prf.
     * Unison now handles permission bits and symbolic links. See the
       manual for details.
     * You can now have different preference files in your .unison
       directory. If you start unison like this
             unison profilename
       (i.e. with just one "anonymous" command-line argument), then the
       file ~/.unison/profilename.prf will be loaded instead of
       default.prf.
     * Some improvements to terminal handling in the text user interface
     * Added a switch -killServer that terminates the remote server
       process when the unison client is shutting down, even when using
       sockets for communication. (By default, a remote server created
       using ssh/rsh is terminated automatically, while a socket server
       is left running.)
     * When started in 'socket server' mode, unison prints 'server
       started' on stderr when it is ready to accept connections. (This
       may be useful for scripts that want to tell when a socket-mode
       server has finished initalization.)
     * We now make a nightly mirror of our current internal development
       tree, in case anyone wants an up-to-the-minute version to hack
       around with.
     * Added a file CONTRIB with some suggestions for how to help us make
       Unison better.


