Irrlicht SDK releases are now taken from branches rather than the Subversion trunk. Once released, bugfixes will continue to be applied to release branches, but new features will only go to the trunk.
The last release was 1.5. You can checkout the 1.5 branch (which may contain bugfixes not in the packaged SDK) using this SVN address:
https://irrlicht.svn.sourceforge.net/sv ... leases/1.5
The previous release was 1.4, which can be obtained from:
https://irrlicht.svn.sourceforge.net/sv ... leases/1.4
The latest development version, with new features, and not guaranteed to be stable at any moment is:
https://irrlicht.svn.sourceforge.net/sv ... icht/trunk
Older versions of Irrlicht (official releases) are still available in the tags/ directory (starting with 1.1).
You can use the 'svn switch' command to change a checked-out repository from one branch to the other. Simply give the URL as a parameter and SVN will update your code just as if you call 'svn update' for the latest revisions.