Is this a mandatory update? If so, is the source on github current?
It's not a mandatory update, no. The previous version still works.
It was most likely built from the v1.4.3.1 tag in the nochowder repo:
https://github.com/nochowderforyou/clams/tree/v1.4.3.1The words "Test-Build" in the links makes me think that maybe it's worth waiting a while before upgrading.