JForum 2.6.2 has been released, which addresses two issues:

It installs and runs on the HSQLDB database.

Fixes a bug that prevents the popup window showing all smilies to be shown when writing a post.

It also includes these two fixes which had been addressed in JForum 2.6.1:

It installs and runs on the Jetty servlet container.

It fixes a bug where deleting posts would cause the corresponding entry in the Moderation Log to be illegible, and break the page layout.

All users can safely upgrade, but if you aren't using Jetty or HsqlDB, or haven't run into one of the bugs, it may not be worth the effort.