The long awaited Zen Cart 1.5.6b Release is scheduled to be initiated on 4/30 (no more changes to Github, file labeling applied), with a zip file created later that week. Here’s the announcement.
1.5.6b promises better interoperability with PHP 7.2+ as well as a number of bug fixes from earlier 1.5.6 releases. The change set from Zen Cart 1.5.6a to the current HEAD is large, containing almost 400 commits!