# 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). Documentation on how to select an MPM is to follow.

### Run-Time Configuration Changes

- The `CacheNegotiatedDocs` directive now takes the argument `on` or `off`. Existing instances of `CacheNegotiatedDocs` should be replaced with `CachNegotiatedDocs on`.
- The `ErrorDocument` directive no longer uses a single 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.
- The `ExtendedStatus` directive no longer exists.
- The `ServerType` directive no longer exists.
- The `CoreDumpDirectory` directive no longer exists.
- Many directives that were in the core server in Apache 1.3 are now in the MPMs.

### Misc Changes

- 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.

### 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 to follow.