CHANGES

                                                         -*- coding: utf-8 -*-

  *) mod_ssl: Add hooks to allow other modules to perform processing at
     several stages of initialization and connection handling.  See
     mod_ssl_openssl.h.  [Jeff Trawick]

  *) mod_http2: disabling PUSH when client sends GOAWAY. Slave connections are 
     reused for several requests, improved performance and better memory use. 
     [Stefan Eissing]  
     
  *) mod_rewrite: Don't implicitly URL-escape the original query string
     when no substitution has changed it (like PR50447 but server context)
     [Evgeny Kotkov <evgeny.kotkov visualsvn.com>]

  *) mod_http2: fixes problem with wrong lifetime of file buckets on main
     connection. [Stefan Eissing]
     
  *) mod_http2: fixes incorrect denial of requests without :authority header.
     [Stefan Eissing]
     
  *) mod_reqtimeout: Prevent long response times from triggering a timeout once
     the request has been fully read.  PR 59045.  [Yann Ylavic]

  *) ap_expr: expression support for variable HTTP2=on|off. [Stefan Eissing]
     
  *) mod_http2: give control to async mpm for keepalive timeouts only when
     no streams are open and even if only after 1 sec delay. Under load, event
     mpm discards connections otherwise too quickly. [Stefan Eissing]
  
  *) mod_ssl: Don't lose track of the SSL context if an unlikely failure occurs
     in ssl_init_ssl_connection().  [Graham Leggett]

  *) mod_rewrite: Add QSL|qslast flag to allow rewrites to files with
     literal question marks in their names. PR 58777. [Eric Covener]

  *) event: use pre_connection hook to properly initialize connection state for
     slave connections. use protocol_switch hook to initialize server config
     early based on SNI selected vhost. 
     [Stefan Eissing]
  
  *) hostname: Test and log useragent_host per-request across various modules,
     including the scoreboard, expression and rewrite engines, setenvif,
     authz_host, access_compat, custom logging, ssl and REMOTE_HOST variables.
     PR55348  [William Rowe]
 
  *) core: Track the useragent_host per-request when mod_remoteip or similar
     modules track a per-request useragent_ip.  Modules should be updated
     to inquire for ap_get_useragent_host() in place of ap_get_remote_host().
     [William Rowe]

  *) core: fix a bug in <UnDefine ...> directive processing. When used, the last
     <Define...>'ed variable was also withdrawn. PR 59019
     [Christophe Jaillet]

  *) mod_http2: Accept-Encoding is, when present on the initiating request, 
     added to push promises. This lets compressed content work in pushes.
     by the client. [Stefan Eissing]

  *) mod_http2: fixed possible read after free when streams were cancelled early
     by the client. [Stefan Eissing]

  *) mod_http2: fixed possible deadlock during connection shutdown. Thanks to 
     @FrankStolle for reporting and getting the necessary data.
     [Stefan Eissing]

  *) mod_http2: fixed apr_uint64_t formatting in a log statement to user proper 
     APR def, thanks to @Sp1l.
     
  *) mod_http2: number of worker threads allowed to a connection is adjusting 
     dynamically. Starting with 4, the number is doubled when streams can be 
     served without block on http/2 connection flow. The number is halfed, when
     the server has to wait on client flow control grants. 
     This can happen with a maximum frequency of 5 times per second. 
     When a connection occupies too many workers, repeatable requests 
     (GET/HEAD/OPTIONS) are cancelled and placed back in the queue. Should that 
     not suffice and a stream is busy longer than the server timeout, the 
     connection will be aborted with error code ENHANCE_YOUR_CALM.
     This does *not* limit the number of streams a client may open, rather the
     number of server threads a connection might use.
     [Stefan Eissing]
  
  *) mod_http2: allowing link header to specify multiple "rel" values, 
     space-separated inside a quoted string. Prohibiting push when Link 
     parameter "nopush" is present.
     [Stefan Eissing]

  *) mod_http2: reworked connection state handling. Idle connections accept a
     GOAWAY from the client without further reply. Otherwise the
     module makes a best effort to send one last GOAWAY to the client.
     
  *) mod_http2: the values from standard directives Timeout and KeepAliveTimeout
     properly are applied to http/2 connections.
     [Stefan Eissing]

  *) mod_http2: idle connections are returned to async mpms. new hook
     "pre_close_connection" used to send GOAWAY frame when not already done.
     Setting event mpm server config "by hand" for the main connection to
     the correct negotiated server.
     [Stefan Eissing]

  *) mod_http2: keep-alive blocking reads are done with 1 second timeouts to
     check for MPM stopping. Will announce early GOAWAY and finish processing
     open streams, then close.
     [Stefan Eissing]

  *) mod_http2: bytes read/written on slave connections are reported via the
     optional mod_logio functions. Fixes PR 58871.

  *) prefork: Initialize the POD when running in ONE_PROCESS (or -X) mode to
     avoid a crash.  [Jan Kaluza, Yann Ylavic]

  *) mod_ssl: When SSLVerify is disabled (NONE), don't force a renegotiation if
     the SSLVerifyDepth applied with the default/handshaken vhost differs from
     the one applicable with the finally selected vhost.  [Yann Ylavic]

  *) core: Ensure that httpd exits with an error status when the MPM fails
     to run.  [Yann Ylavic]

  *) mod_ssl: Fix a possible memory leak on restart for custom [EC]DH params.
     [Jan Kaluza, Yann Ylavic]

  *) mod_ssl: Add SSLOCSPProxyURL to add the possibility to do all queries
     to OCSP responders through a HTTP proxy. [Ruediger Pluem]

  *) mod_proxy: Play/restore the TLS-SNI on new backend connections which
     had to be issued because the remote closed the previous/reusable one
     during idle (keep-alive) time.  [Yann Ylavic]

  *) mod_cache_socache: Fix a possible cached entity body corruption when it
     is received from an origin server in multiple batches and forwarded by
     mod_proxy.  [Yann Ylavic]

  *) core: Add expression support to SetHandler.
     [Eric Covener]

  *) mod_remoteip: Prevent an external proxy from presenting an internal
     proxy. PR 55962. [Mike Rumph]

  *) core: Prevent a server crash in case of an invalid CONNECT request with
     a custom error page for status code 400 that uses server side includes.
     PR 58929 [Ruediger Pluem]

  *) mod_ssl: handle TIMEOUT on empty SSL input as non-fatal, returning 
     APR_TIMEUP and preserving connection state for later retry.
     [Stefan Eissing]
     
  *) mod_ssl: Save some TLS record (application data) fragmentations by
     including the last and subsequent suitable buckets when coalescing.
     [Yann Ylavic]

  *) mod_proxy_fcgi: Suppress HTTP error 503 and message 01075, 
     "Error dispatching request", when the cause appears to be 
     due to the client closing the connection. 
     PR58118.  [Tobias Adolph <adolph lrz.de>]

  *) mod_cgid: Message AH02550, failure to flush a response to the client,
     is now logged at TRACE1 level to match the underlying core output filter
     severity.  [Eric Covener]

  *) mime.types: add common extension "m4a" for MPEG 4 Audio.
     PR 57895 [Dylan Millikin <dylan.millikin gmail.com>]

  *) Added many log numbers to log statements that had none.
     [Rainer Jung]

  *) mod_log_config: Add GlobalLog to allow a globally defined log to
     be inherited by virtual hosts that define a CustomLog.
     [Edward Lu]

  *) mod_http2: connections how keep a "push diary" where hashes of already
     pushed resources are kept. See directive H2PushDiarySize for managing this.
     Push diaries can be initialized by clients via the "Cache-Digest" request
     header. This carries a base64url encoded. compressed Golomb set as described
     in https://datatracker.ietf.org/doc/draft-kazuho-h2-cache-digest/
     Introduced a status handler for HTTP/2 connections, giving various counters
     and statistics about the current connection, plus its cache digest value
     in a JSON record. Not a replacement for more HTTP/2 in the server status. 
     Configured as
     <Location "/http2-status">
         SetHandler http2-status
     </Location>
     [Stefan Eissing]
  
  *) mod_http2: Fixed flushing of last GOAWAY frame. Previously, that frame
     did not always reach the client, causing some to fail the next request.
     Fixed calculation of last stream id accepted as described in rfc7540. 
     Reading in KEEPALIVE state now correctly shown in scoreboard. 
     Fixed possible race in connection shutdown after review by Ylavic. 
     Fixed segfault on connection shutdown, callback ran into a semi dismantled session. 
     [Stefan Eissing]

  *) mod_http2: Added support for experimental accept-push-policy draft
     (https://tools.ietf.org/html/draft-ruellan-http-accept-push-policy-00). Clients
     may now influence server pushes by sending accept-push-policy headers.
     [Stefan Eissing]

  *) mod_http2: new r->subprocess_env variables HTTP2 and H2PUSH, set to "on"
     when available for request.
     [Stefan Eissing]