Upgrading to 2.4 from 2.2 - Apache HTTP Server Version 2.4








Modules | Directives | FAQ | Glossary | Sitemap
Apache HTTP Server Version 2.4



Apache > HTTP Server > Documentation > Version 2.4Upgrading to 2.4 from 2.2

Available Languages:  en  |
 fr 


  In order to assist folks upgrading, we maintain a document
  describing information critical to existing Apache HTTP Server 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.  Application and module developers
  can find a summary of API changes in the API updates overview.

  This document describes changes in server behavior that might
  require you to change your configuration or how you use the server
  in order to continue using 2.4 as you are currently using 2.2.
  To take advantage of new features in 2.4, see the New Features
  document.

  This document describes only the changes from 2.2 to 2.4.  If you
  are upgrading from version 2.0, you should also consult the 2.0 to 2.2
  upgrading document.


 Compile-Time Configuration Changes
 Run-Time Configuration Changes
 Misc Changes
 Third Party Modules
 Common problems when upgrading
See alsoOverview of new features in
  Apache HTTP Server 2.4Comments


Compile-Time Configuration Changes
    

    The compilation process is very similar to the one used in
    version 2.2.  Your old configure command line (as
    found in build/config.nice in the installed server
    directory) can be used in most cases.  There are some changes in
    the default settings.  Some details of changes:

    
      These modules have been removed: mod_authn_default,
      mod_authz_default, mod_mem_cache.  If you were using
      mod_mem_cache in 2.2, look at mod_cache_disk in
      2.4.

      All load balancing implementations have been moved to
      individual, self-contained mod_proxy submodules, e.g.
      mod_lbmethod_bybusyness.  You might need
      to build and load any of these that your configuration
      uses.

      Platform support has been removed for BeOS, TPF, and
      even older platforms such as A/UX, Next, and Tandem.  These were
      believed to be broken anyway.

      configure: dynamic modules (DSO) are built by default

      configure: By default, only a basic set of modules is loaded. The
      other LoadModule directives are commented
      out in the configuration file.

      configure: the "most" module set gets built by default

      configure: the "reallyall" module set adds developer modules
      to the "all" set
    

  

Run-Time Configuration Changes
    
    There have been significant changes in authorization configuration,
    and other minor configuration changes, that could require changes to your 2.2
    configuration files before using them for 2.4.

    Authorization
      

      Any configuration file that uses authorization will likely
      need changes.

    You should review the Authentication,
    Authorization and Access Control Howto, especially the section
    Beyond just authorization
    which explains the new mechanisms for controlling the order in
    which the authorization directives are applied.

    Directives that control how authorization modules respond when they don't match
    the authenticated user have been removed: This includes 
    AuthzLDAPAuthoritative, AuthzDBDAuthoritative, AuthzDBMAuthoritative, 
    AuthzGroupFileAuthoritative, AuthzUserAuthoritative,
    and AuthzOwnerAuthoritative.   These directives have been replaced by the
    more expressive RequireAny, 
    RequireNone, and
    RequireAll.

    If you use mod_authz_dbm, you must port your 
    configuration to use Require dbm-group ... in place
    of Require group ....

    Access control
      

      In 2.2, access control based on client hostname, IP address,
      and other characteristics of client requests was done using the
      directives Order, Allow, Deny, and Satisfy.

      In 2.4, such access control is done in the same way as other
      authorization checks, using the new module
      mod_authz_host.  The old access control idioms
      should be replaced by the new authentication mechanisms,
      although for compatibility with old configurations, the new
      module mod_access_compat is provided.

      Mixing old and new directives
      Mixing old directives like Order, Allow or Deny with new ones like
      Require is technically possible 
      but discouraged. mod_access_compat was created to support 
      configurations containing only old directives to facilitate the 2.4 upgrade. 
      Please check the examples below to get a better idea about issues that might arise.
      
      

      Here are some examples of old and new ways to do the same
      access control.

      In this example, there is no authentication and all requests are denied.
      2.2 configuration:Order deny,allow
Deny from all

      2.4 configuration:Require all denied


      In this example, there is no authentication and all requests are allowed.
      2.2 configuration:Order allow,deny
Allow from all

      2.4 configuration:Require all granted


      In the following example, there is no authentication and all hosts in the example.org domain
      are allowed access; all other hosts are denied access.

      2.2 configuration:Order Deny,Allow
Deny from all
Allow from example.org

      2.4 configuration:Require host example.org


      In the following example, mixing old and new directives leads to 
      unexpected results.
 
      Mixing old and new directives: NOT WORKING AS EXPECTEDDocumentRoot "/var/www/html"

<Directory "/">
    AllowOverride None
    Order deny,allow
    Deny from all
</Directory>

<Location "/server-status">
    SetHandler server-status
    Require local
</Location>

access.log - GET /server-status 403 127.0.0.1
error.log - AH01797: client denied by server configuration: /var/www/html/server-status

      Why httpd denies access to servers-status even if the configuration seems to allow it?
        Because mod_access_compat directives take precedence
        over the mod_authz_host one in this configuration 
        merge scenario.

      This example conversely works as expected:

      Mixing old and new directives: WORKING AS EXPECTEDDocumentRoot "/var/www/html"

<Directory "/">
    AllowOverride None
    Require all denied
</Directory>

<Location "/server-status">
    SetHandler server-status
    Order deny,allow
    Deny from all
    Allow From 127.0.0.1
</Location>

access.log - GET /server-status 200 127.0.0.1
 
      So even if mixing configuration is still
        possible, please try to avoid it when upgrading: either keep old directives and then migrate
        to the new ones on a later stage or just migrate everything in bulk.  
      
    

     In many configurations with authentication, where the value of the
     Satisfy was the default of ALL, snippets
     that simply disabled host-based access control are omitted:

      2.2 configuration:# 2.2 config that disables host-based access control and uses only authentication
Order Deny,Allow
Allow from all
AuthType Basic
AuthBasicProvider file
AuthUserFile /example.com/conf/users.passwd
AuthName secure
Require valid-user

      2.4 configuration:# No replacement of disabling host-based access control needed
AuthType Basic
AuthBasicProvider file
AuthUserFile /example.com/conf/users.passwd
AuthName secure
Require valid-user


     In configurations where both authentication and access control were meaningfully combined, the 
        access control directives should be migrated. This example allows requests meeting both criteria:
      2.2 configuration:Order allow,deny
Deny from all
# Satisfy ALL is the default
Satisfy ALL
Allow from 127.0.0.1
AuthType Basic
AuthBasicProvider file
AuthUserFile /example.com/conf/users.passwd
AuthName secure
Require valid-user

      2.4 configuration:AuthType Basic
AuthBasicProvider file
AuthUserFile /example.com/conf/users.passwd
AuthName secure
<RequireAll>
  Require valid-user
  Require ip 127.0.0.1
</RequireAll>


     In configurations where both authentication and access control were meaningfully combined, the 
        access control directives should be migrated. This example allows requests meeting either criteria:
      2.2 configuration:Order allow,deny
Deny from all
Satisfy any
Allow from 127.0.0.1
AuthType Basic
AuthBasicProvider file
AuthUserFile /example.com/conf/users.passwd
AuthName secure
Require valid-user

      2.4 configuration:AuthType Basic
AuthBasicProvider file
AuthUserFile /example.com/conf/users.passwd
AuthName secure
# Implicitly <RequireAny>
Require valid-user
Require ip 127.0.0.1


    

    Other configuration changes
      

      Some other small adjustments may be necessary for particular
      configurations as discussed below.

      
        MaxRequestsPerChild has been renamed to
        MaxConnectionsPerChild,
        describes more accurately what it does. The old name is still
        supported.

        MaxClients has been renamed to
        MaxRequestWorkers,
        which describes more accurately what it does. For async MPMs, like
        event, the maximum number of clients is not
        equivalent than the number of worker threads. The old name is still
        supported.

        The DefaultType
        directive no longer has any effect, other than to emit a
        warning if it's used with any value other than
        none.  You need to use other configuration
        settings to replace it in 2.4.
        

        AllowOverride now
        defaults to None.

        EnableSendfile now
        defaults to Off.

        FileETag now
        defaults to "MTime Size" (without INode).

        mod_dav_fs: The format of the DavLockDB file has changed for
        systems with inodes.  The old DavLockDB file must be deleted on
        upgrade.
        

        KeepAlive only
        accepts values of On or Off.
        Previously, any value other than "Off" or "0" was treated as
        "On".

        Directives AcceptMutex, LockFile, RewriteLock, SSLMutex,
        SSLStaplingMutex, and WatchdogMutexPath have been replaced
        with a single Mutex
        directive.  You will need to evaluate any use of these removed
        directives in your 2.2 configuration to determine if they can
        just be deleted or will need to be replaced using Mutex.

        mod_cache: CacheIgnoreURLSessionIdentifiers
        now does an exact match against the query string instead of a
        partial match.  If your configuration was using partial
        strings, e.g. using sessionid to match
        /someapplication/image.gif;jsessionid=123456789,
        then you will need to change to the full string
        jsessionid.
        

        mod_cache: The second parameter to 
        CacheEnable only
        matches forward proxy content if it begins with the correct
        protocol. In 2.2 and earlier, a parameter of '/' matched all
        content.

        mod_ldap: LDAPTrustedClientCert is now
        consistently a per-directory setting only.  If you use this
        directive, review your configuration to make sure it is
        present in all the necessary directory contexts.

        mod_filter: FilterProvider syntax has changed and
        now uses a boolean expression to determine if a filter is applied.
        

        mod_include:
            
            The #if expr element now uses the new expression parser. The old syntax can be
            restored with the new directive SSILegacyExprParser.
            
            An SSI* config directive in directory scope no longer causes
            all other per-directory SSI* directives to be reset to their
            default values.
            
        

        mod_charset_lite: The DebugLevel
        option has been removed in favour of per-module LogLevel configuration.
        

        mod_ext_filter: The DebugLevel
        option has been removed in favour of per-module LogLevel configuration.
        

        mod_proxy_scgi: The default setting for
        PATH_INFO has changed from httpd 2.2, and
        some web applications will no longer operate properly with
        the new PATH_INFO setting.  The previous setting
        can be restored by configuring the proxy-scgi-pathinfo
        variable.

        mod_ssl: CRL based revocation checking
        now needs to be explicitly configured through SSLCARevocationCheck.
        

        mod_substitute: The maximum line length is now
        limited to 1MB.
        

        mod_reqtimeout: If the module is loaded, it
        will now set some default timeouts.

        mod_dumpio: DumpIOLogLevel
        is no longer supported.  Data is always logged at LogLevel trace7.

        On Unix platforms, piped logging commands configured using
        either ErrorLog or
        CustomLog were invoked using
        /bin/sh -c in 2.2 and earlier.  In 2.4 and later,
        piped logging commands are executed directly.  To restore the
        old behaviour, see the piped logging
        documentation.

      
    
  

Misc Changes
    

    
      mod_autoindex: will now extract titles and
      display descriptions for .xhtml files, which were previously
      ignored.

      mod_ssl: The default format of the *_DN
      variables has changed. The old format can still be used with the new
      LegacyDNStringFormat argument to SSLOptions. The SSLv2 protocol is
      no longer supported. SSLProxyCheckPeerCN
	   and SSLProxyCheckPeerExpire
	   now default to On, causing proxy requests to HTTPS hosts
	  with bad or outdated certificates to fail with a 502 status code (Bad 
	  gateway)

      htpasswd now uses MD5 hash by default on
      all platforms.

      The NameVirtualHost
      directive no longer has any effect, other than to emit a
      warning.  Any address/port combination appearing in multiple
      virtual hosts is implicitly treated as a name-based virtual host.
      

      mod_deflate will now skip compression if it knows
      that the size overhead added by the compression is larger than the data
      to be compressed.
      

      Multi-language error documents from 2.2.x may not work unless
      they are adjusted to the new syntax of mod_include's
      #if expr= element or the directive
      SSILegacyExprParser is
      enabled for the directory containing the error documents.
      

      The functionality provided by mod_authn_alias
      in previous versions (i.e., the AuthnProviderAlias directive)
      has been moved into mod_authn_core.  
      

      The RewriteLog and RewriteLogLevel directives have been removed.
      This functionality is now provided by configuring the appropriate
      level of logging for the mod_rewrite module using
      the LogLevel directive.
      See also the mod_rewrite logging
      section.

    

  

Third Party Modules
    
    All modules must be recompiled for 2.4 before being loaded.

    Many third-party modules designed for version 2.2 will
    otherwise work unchanged with the Apache HTTP Server version 2.4.
    Some will require changes; see the API
    update overview.
  

Common problems when upgrading
    
    Startup errors:
    
      Invalid command 'User', perhaps misspelled or defined by a module not included in the server configuration - load module mod_unixd
      Invalid command 'Require', perhaps misspelled or defined by a module not included in the server configuration, or
Invalid command 'Order', perhaps misspelled or defined by a module not included in the server configuration
 - load module mod_access_compat, or update configuration to 2.4 authorization directives.
      Ignoring deprecated use of DefaultType in line NN of /path/to/httpd.conf - remove DefaultType
      and replace with other configuration settings.
      Invalid command 'AddOutputFilterByType', perhaps misspelled 
      or defined by a module not included in the server configuration
       - AddOutputFilterByType 
      has moved from the core to mod_filter, which must be loaded.
    
    Errors serving requests:
    
      configuration error:  couldn't check user: /path -
      load module mod_authn_core.
      .htaccess files aren't being processed - Check for an
      appropriate AllowOverride directive;
      the default changed to None in 2.4.
    
    

  

Available Languages:  en  |
 fr 

Copyright 2026 The Apache Software Foundation.Licensed under the Apache License, Version 2.0.
Modules | Directives | FAQ | Glossary | Sitemap