The release branch for scap has tags for 3.9.1-1
Instructions available on Wikitech.
This is a bugfix release:
scap (3.9.1-1) unstable; urgency=low [ Giuseppe Lavagetto ] * Fix OpcacheManager.invalidate_all() -- Tyler Cipriani <tcipriani@wikimedia.org> Wed, 27 Feb 2019 13:25:12 -0700