@Joomla_Direct Yes, Captions is compatible with Joomla 1.5. A new version will also be released this week.
10 December 2012
JCE 2.3.1 released
This update fixes a few bugs that unfortunately weren't found in the beta / release candidate testing phase.
A full changelog (from JCE 2.2.x) is available here
Installation and Updating
Instructions for installing JCE 2.3.0 are available here
JCE can also be updated from previous versions using the JCE Updater in Joomla! 1.5 and 2.5 or using the Joomla! Update Manager in Joomla! 2.5 and 3.0
Clear your browser cache after updating from a previous JCE installation
JCE 2.3.0 can be download from here