Apache 2.2 的最新一个版本 2.2.4 出来了！这个版本主要是纠正了上一个版本的一些bug，没有什么新的特性，更正的bug列表如下，其中有很多涉及proxy和cache模块的，下载地址：

http://www.apache.org/dist/httpd/

Changes with Apache 2.2.4

  *) mod_isapi: Correctly present SERVER_PORT_SECURE.
     PR: 40573.  [Matt Eaton ]

  *) Allow htcacheclean, httxt2dbm, and fcgistarter to link apr/apr-util
     statically like the older support programs.
     [Eric Covener ]

  *) core: Fix NONBLOCK status of listening sockets on restart/graceful
     PR 37680.  [Darius Davis ]

  *) mod_deflate: Rework inflate output and deflate output filter to fix several
     issues: Incorrect handling of flush buckets, potential memory leaks,
     excessive memory usage in inflate output filter for large compressed
     content. PR 39854. [Ruediger Pluem, Nick Kew, Justin Erenkrantz]

  *) mod_mem_cache: Memory leak fix: Unconditionally free the buffer.
     [Davi Arnaut ]

  *) Allow mod_dumpio to log at other than DEBUG levels via
     the new DumpIOLogLevel directive. [Jim Jagielski]

  *) rotatelogs: Improve error message for open failures.  PR 39487.
     [Joe Orton]

  *) mod_dbd: share per-request database handles across subrequests
     and internal redirects [Chris Darroch]

  *) mod_dbd: key connection pools to virtual hosts correctly even when
     ServerName is unset/unavailable [Graham Leggett]

  *) Better detection and clean up of ldap connection that has been
     terminated by the ldap server.  PR 40878.
     [Rob Baily ]

  *) mod_mem_cache: Convert mod_mem_cache to use APR memory pool functions
     by creating a root pool for object persistence across requests. This
     also eliminates the need for custom serialization code.
     [Davi Arnaut ]

  *) mod_authnz_ldap: Add an AuthLDAPRemoteUserAttribute directive. If
     set, REMOTE_USER will be set to this attribute, rather than the
     username supplied by the user. Useful for example when you want users
     to log in using an email address, but need to supply a userid instead
     to the backend.  [Graham Leggett]

  *) mod_cgi and mod_cgid: Don't use apr_status_t error return
     from input filters as HTTP return value from the handler.
     PR 31579.  [Nick Kew]

  *) mod_cache: Eliminate a bogus error in the log when a filter returns
     AP_FILTER_ERROR.  [Niklas Edmundsson ]

  *) core: Fix issue which could cause piped loggers to be orphaned and never
     terminate after a graceful restart.  PR 40651.  [Joe Orton, Ruediger Pluem]

  *) core: Fix address-in-use startup failure caused by corruption of the list
     of listen sockets in some configurations with multiple generic Listen
     directives.  [Jeff Trawick]

  *) mod_headers: Support regexp-based editing of HTTP headers.  [Nick Kew]

  *) mod_proxy: Add explicit flushing feature. When Servlet container sends AJP
     body message with size 0, this means that Servlet container has asked for
     an explicit flush. Create flush bucket in that case. This feature has been
     added to the recent Tomcat versions without breaking the AJP protocol.
     [Mladen Turk]

  *) mod_proxy_balancer: Set the new environment variable BALANCER_ROUTE_CHANGED
     if a worker with a route different from the one supplied by the client
     had been chosen or if the client supplied no routing information for
     a balancer with sticky sessions.  [Ruediger Pluem]

  *) mod_proxy_balancer: Add information about the route, the sticky session
     and the worker used during a request as environment variables. PR 39806.
     [Brian ]

  *) mod_proxy: Don't try to use dead backend connection. PR 37770.
     [Olivier BOEL ]

  *) mod_proxy_balancer: Extract stickysession routing information contained as
     parameter in the URL correctly. PR 40400.
     [Ruediger Pluem, Tomokazu Harada ]

  *) mod_proxy_ajp: Added cping/cpong support for the AJP protocol.
     A new worker directive ping=timeout will cause CPING packet
     to be send expecting CPONG packet within defined timeout. 
     In case the backend is too busy this will fail instead
     sending the full header.  [Mladen Turk]

  *) mod_disk_cache: Make sure that only positive integers are accepted
     for the CacheMaxFileSize and CacheMinFileSize parameters in the
     config file. PR39380.  [Niklas Edmundsson ]

  *) mod_cache: From RFC3986 (section 6.2.3.) if a URI contains an
     authority component and an empty path, the empty path is to be equivalent
     to "/". It explicitly cites the following four URIs as equivalents:
       http://example.com
       http://example.com/
       http://example.com:/
       http://example.com:80/
     [Davi Arnaut ]

  *) mod_cache: Don't cache requests with a expires date in the past;
     otherwise mod_cache will always try to cache the URL. This bug
     might lead to numerous rename() errors on win32 if the URL was
     previously cached. [Davi Arnaut ]

  *) core: Deal with the widespread use of apr_status_t return values
     as HTTP status codes, as documented in PR#31759 (a bug shared by
     the default handler, mod_cgi, mod_cgid, mod_proxy, and probably
     others). PR31759.  [Jeff Trawick, Ruediger Pluem, Joe Orton]

  *) mod_ext_filter: Handle filter names which include capital letters.
     PR 40323.  [Jeff Trawick]

  *) mod_isapi: Avoid double trailing slashes in HSE_REQ_MAP_URL_TO_PATH
     support.  Also corrects the slashes for Windows.
     PR 15993.  [William Rowe]

  *) mod_isapi: Handle "HTTP/1.1 200 OK" style status lines correctly, the
     token parser worked while the resulting length was misinterpreted.
     PR 29098.  [Brock Bland ]

  *) mod_isapi: Return 0 (failure) for more of the various ap_pass_brigade
     attempts to stream the response at the client.  Log these as well.
     PR 30022, 40470.  [William Rowe, Matt Eaton ]

  *) mod_isapi: Ensure we walk through all the methods the developer may have
     employed to report their HTTP status result code.
     PR 16637 30033 28089.  [Matt Lewandowsky , William Rowe]

  *) mod_echo: Fix precedence problem in if statement. PR 40658.
     [Larry Cipriani ]

  *) mod_mime_magic: Fix precedence problem in if statement. PR 40656.
     [Larry Cipriani ]

  *) The full server version information is now included in the error log at
     startup as well as server status reports, irrespective of the setting
     of the ServerTokens directive.  ap_get_server_version() is now deprecated,
     and is replaced by ap_get_server_banner() and ap_get_server_description().
     [Jeff Trawick]

  *) mod_proxy_balancer: Workers can now be defined as part of
     a balancer cluster "set" in which members of a lower-numbered set
     are preferred over higher numbered ones.  [Jim Jagielski]

  *) mod_proxy_balancer: Workers can now be defined as "hot standby" which
     will only be used if all other workers are unusable (eg: in
     error or disabled). Also, the balancer-manager displays the election
     count and I/O counts of all workers.  [Jim Jagielski]

  *) mod_proxy_ajp: Close connection to backend if reading of request body
     fails. PR 40310.  [Ian Abel ]

  *) mod_proxy_balancer: Retry worker chosen by route / redirect worker if
     it is in error state before sending "Service Temporarily Unavailable".
     PR 38962.  [Christian Boitel ]