The Apache HTTP Server Project is an effort to develop and maintain an open-source HTTP server for modern operating systems including UNIX and Windows NT. The goal of this project is to provide a secure, efficient and extensible server that provides HTTP services in sync with the current HTTP standards.Apache httpd has been the most popular web server on the Internet since April 1996, and celebrated its 17th birthday as a project this February.
Multiple MPMs can now be built as loadable modules at compile time. The MPM of choice can be configured at run time.
The Event MPM is no longer experimental but is now fully supported.
Better support for asynchronous read/write for supporting MPMs and platforms.
The LogLevel can now be configured per module and per directory. New levels trace1 to trace8 have been added above the debug log level.
A new expression parser allows to specify complex conditions using a common syntax in directives like SetEnvIfExpr, RewriteCond, Header and others.