The following is a list of the main new features of Apache 2. For detailed information about version 2.0 of the Apache HTTP server, refer to http://httpd.apache.org/docs-2.0/en/.
Multiple queries may be processed as threads or processes. The process management has been relocated to a separate module, called the multiprocessing module (MPM). Depending on the MPM, Apache 2 responds to queries in different ways, with different effects on the performance and the use of modules. Details are provided below.
The innards of Apache have been thoroughly revised. Apache now uses a new, special base library (Apache portable runtime, APR) as the interface to system functions and for memory management. Important and widespread modules, such as mod_gzip (successor: mod_deflate) and mod_ssl, which have a profound impact on the processing of requests, are now integrated more fully in Apache.
Apache 2 supports the Internet protocol IPv6.
A new mechanism enables manufacturers of modules to specify the desired loading sequence for modules. Thus, users are no longer required to do this themselves. The order in which modules are executed is often significant. Previously, it was determined by means of the loading sequence. For example, a module that only gives authenticated users access to certain resources must be run first to prevent the pages from being displayed to users who do not have any access permissions.
Queries to and replies from Apache can be processed with filters.
Support for files that are larger than 2 GB (large file support, LFS) on 32-bit systems.
Some of the newer modules are only available for Apache 2.
Multilanguage error responses.