Release Notes 2.8-m4 ("Milestone 4")
Do not use this release to upgrade your production systems.
For all production use and testing of Confluence, please use the latest official release.
Confluence 2.8-m4 is a milestone development release for 2.8. This is a public development release (DR) leading up to Confluence 2.8. Development releases are a snapshot of our work in progress, allowing our customers and especially plugin-developers to see what we're up to.
Who should upgrade?
Development releases are not production ready. Development releases are snapshots of the ongoing Confluence development process. While we try to keep these releases stable, they have not undergone the same degree of testing as a full release, and could contain features that are incomplete or may change or be removed before the next full release.
No upgrade path. Because development releases represent work in progress, we cannot provide a supported upgrade path between development releases, or from any development release to a final release. You may not be able to migrate any data you store in a Confluence development release to a future Confluence release.
Atlassian does not provide support for development releases.
Our milestone releases aim to provide plugin developers with an opportunity to see the latest changes in the code.
Each milestone release has passed all our automatic tests, and has been used for one week on our official internal Confluence server. Most of the issues solved have been reviewed too.
However, since our milestones releases are timeboxed (i.e. they get released every two weeks, no matter how far we have come implementing features and bugfixes), there is always a chance that we have new known bugs, which are scheduled to be fixed in the next milestone, or completely new bugs unknown even to us.
Milestone releases have not been load- or stress-tested. So, for example, they might behave well on a small installation but show severe problems when subjected to many users.
Upgrade Procedure
Follow the normal upgrade instructions to upgrade from Confluence 2.7.x to this release. We strongly recommend that you backup your confluence-home directory and database before upgrading!
Downloads
All development releases are available from Development Releases on the Atlassian website.
Issues resolved or improved in this release
This release mainly fixes bugs and glitches of the previous milestone, and extends the functionality slightly. You will notice that a new dropdown-menu has been added which allows you to access the browse-space actions easier, and that most macros now honor the new page ordering that can be set in recently added page-reorder-component.
We had forgotten to release the source code of the previous milestones, this has been taken care of now, thanks Alain from Adaptavist for pointing this out! 
The coolest improvement however is that we are able to deliver the first ShipIt 7 project in this milestone - less than two weeks since the actual event! (see http://blogs.atlassian.com/developer/2007/09/atlassian_ShipIt_day_vi.html) for an overview of ShipIt 6 last year). Use the new drop-down menu to "Browse Labels", select one of the most popular ones, and you will now be able to filter by multiple labels - just increase or decrease the number of labels by using the plus- and minus-signs next to the related labels. Admittedly the UI still needs some finishing touches, but it works fine already and it will make 21 voters happy once released officially (http://jira.atlassian.com/browse/CONF-4577). More ShipIt-projects can be expected to make it into M5 and M6.
You can view the complete list of fixes and newly implemented features in JIRA. They contain all the issues resolved during development of 2.8, not just the ones fixed since the previous milestone.
Known problems
There are still a few known bugs in this release, most noticeably the broken printable view (CONF-10583) which will be fixed soon. Please continue reporting problems through JIRA, your feedback has been very helpful and a lot of it has been incorporated already.
The CacheManager API has changed in milestone 4, and all plugins that use the old CacheManager interface will be broken (CONF-10602). In milestone 5, Confluence has a workaround for plugins that get the cacheManager injected. That is, the following code will work correctly in 2.8-m5 (but is currently broken in 2.8-m4):
import com.atlassian.user.impl.cache.CacheManager;
public class MyClass {
private CacheManager cacheManager;
public void setCacheManager(CacheManager cacheManager) {
this.cacheManager = cacheManager;
}
}
Plugins that access the CacheManager not via dependency injection, but statically through the ContainerManager will fail at runtime with a ClassCastException. These plugins should be rewritten to use dependency injection, or use the new com.atlassian.cache.CacheManager interface. The following code is broken in 2.8-m4, and will continue to be broken for the final release of 2.8:
CacheManager cacheManager = (CacheManager) ContainerManager.getComponent("cacheManager");
Plugins that wish to avoid using the deprecated CacheManager interface should change to use com.atlassian.cache.CacheManager.