The bundled extensions in the download are:

• eZ Online Editor 5.0.4 (based on TinyMCE)
• eZ OpenOffice.org extension 2.4.0

During the setup wizard, updated versions of eZ Publish Website Interface or eZ Flow can be selected which also install the following extensions:

• eZ Website Toolbar (separated from eZ Web site)
• eZ JS Core (base library for client side Javascript and Ajax functions)
• eZ Star Rating (based on a contribution by Bruce Morrison)
• eZ Google Maps Location (contributed by Joe Kepley)

The main new kernel features are

• A new cluster file handler, which can be used with distributed filesystems such as NFS
• Improved LDAP support
• Full PHP 5.3 compatibility

Other extensions related to 4.2.0rc2 available are

• eZ Find 2.1rc2
• eZ SI 1.2.0
• eZ Survey 2.1rc2

Downloads and changelog

You can find downloads here

The . changelog for the kernel is available here

Notes on backwards compatibility

Since eZ Publish 4.2.0-alpha1

INI setting changes

image.ini
  [AnimatedGIF]
  DisallowedFilters[] defaults to empty
  AllowedFilters[] defaults to geometry/*
  This change is to ensure that animated GIFs can be resized using default settings. 

Change of behaviour

• eZLDAPUser::loginUser

  ldap.ini setting LDAPFollowReferrals is introduced and set to 0 by default as LDAP code did not work with most AD setups. LDAP_OPT_REFERRALS was earlier not set at all, thus enabled.

• User / Forgotpassword

  Links in the mail generated by the user/forgotpasswordmail.tpl template will no longer have the hostname pre-pended to them. This must be handled in the template. The change was done in order to be consistent with other emails sent by eZ Publish.

Renamed methods

• eZSoapRequest::namespace() -> eZSoapRequest::ns()

  Renamed for php 5.3 support, see issue #13825

Since eZ Publish 4.2.0-beta1

Change of behaviour

• The wildcard cache files (var/xxx/cache/wildcard/wildcard_<md5>_xxx.php) used to contain callback functions. They now contain PHP arrays like most other caches. Naming remains completely the same.

• API consolidation:all classes of eZURLWildcard now have a proper visibility. Lots of them have been made protected.
  
  • Public methods: eZURLWildcard, definition, asArray, store, removeAll, removeByIDs, fetch, fetchBySourceURL, fetchList, fetchListCount, translate, expireCache, fetchCacheFile (callback for the cluster handler).
  • Signatures for the public methods haven't changed.

• An HTTP 1.1 500 error will be thrown when a fatal error occurs.

Removed features

• The deprecated form module has been removed.

Removed methods

• Deprecated and removed eZExpiryHandler::IsModified() as it wasn't useful. Use the property eZExpiryHandler->IsModified instead.

Since eZ Publish 4.2.0-rc1

• Administration interface pagelayout.tpl

  Included automatically left menu template for the default_navigation_part
  ez $part_name navigationpart => parts/$part_name/menu.tpl requires to
  have right template in place. This is required for module views which has
  default_navigation_part defined. Ref. to the enhancement request # 14654.

Since eZ Publish 4.2.0-rc2

NA

Upgrading

Upgrading from earlier releases is not recommended yet, but if you want there is a database upgrade script needed which you can find under update/database/<db type>/4.2/unstable