### Apache HTTP Server

# Upgrading to 2.0 from 1.3

In order to assist folks upgrading, we maintain a document describing information critical to existing Apache users. These are intended to be brief notes, and you should be able to find more information in either the New Features document, or in the `src/CHANGES` file.

### Compile-Time Configuration Changes

- Apache now uses an `autoconf` and `libtool` system for configuring the build processes. Using this system is similar to, but not the same as, using the APACI system in Apache 1.3. Further documentation to follow.
- In addition to the usual selection of modules which you can choose to compile, Apache 2.0 has moved the main part of request processing into Multi-Processing Modules (MPMs).

### Run-Time Configuration Changes

- Many directives that were in the core server in Apache 1.3 are now in the MPMs. If you wish the behavior of the server to be as similar as possible to the behavior of Apache 1.3, you should select the prefork MPM. Other MPMs will have different directives to control process creation and request processing.
- The `CacheNegotiatedDocs` directive now takes the argument `on` or `off`. Existing instances of `CacheNegotiatedDocs` should be replaced with `CacheNegotiatedDocs on`.
- The `ErrorDocument` directive no longer uses a quote at the beginning of the argument to indicate a text message. Instead, you should enclose the message in double quotes. For example, existing instances of

  > `ErrorDocument 403 "Some Message`

  should be replaced with

  > `ErrorDocument 403 "Some Message"`

  As long as the second argument is not a valid URL or pathname, it will be treated as a text message.
- The `AccessConfig` and `ResourceConfig` directives no longer exist. Existing instances of these directives can be replaced with the `Include` directive which has equivalent functionality. If you were making use of the default values of these directives without including them in the configuration files, you may need to add `Include conf/access.conf` and `Include conf/srm.conf` to your httpd.conf. In order to assure that Apache reads the configuration files in the same order as was implied by the older directives, the `Include` directives should be placed at the end of httpd.conf, with the one for `srm.conf` preceding the one for `access.conf`.
- The `BindAddress` directive no longer exists. Equivalent functionality is provided with the more flexible `Listen` directive.
- The `ExtendedStatus` directive no longer exists. Status reporting has been completely rewritten to take advantage of the new MPM system.
- The `ServerType` directive no longer exists. The method used to serve requests is now determined by the selection of MPM. There is currently no MPM designed to be launched by inetd.
- The mod_log_agent and mod_log_referer modules which provided the `AgentLog`, `RefererLog` and `RefererIgnore` directives have been removed. Agent and referer logs are still available using the CustomLog directive of mod_log_config.
- The `AddModule` and `ClearModuleList` directives no longer exist. These directives where used to ensure that modules could be enabled in the correct order. The new Apache 2.0 API allows modules to explicitly specify their ordering, eliminating the need for these directives.

### Misc Changes

- Graceful restarts of the server are now executed by signaling the parent process with `WINCH` rather than `USR1`.
- The `httpd` command line option `-S` which was used for printing the virtual host configuration has been replaced by `-t -D DUMP_VHOSTS`.
- The `httpd` command line option `-X` has been removed. Most MPMs allow the same functionality to be requested by using the `-D ONE_PROCESS` command line option. In addition, a `-D NO_DETACH` command line option is available.
- The module mod_auth_digest, which was experimental in Apache 1.3 is now a standard module.
- The mod_mmap_static module, which was experimental in Apache 1.3 has been replaced with mod_file_cache.
- The distribution has been completely reorganized so that it no longer contains an independent `src` directory. Instead, the sources are logically organized under the main distribution directory, and installations of the compiled server should be directed to a separate directory.

### Third Party Modules

Extensive changes were made to the server API in Apache 2.0. Existing modules designed for the Apache 1.3 API will not work in Apache 2.0 without modification. Details are provided in the developer documentation.

### Apache HTTP Server