Comment 39 for bug 2027716

The current ppa contents include the recent security update for samba, *EXCEPT* for the bionic build, which did not receive said security update.

Specifically regarding your question:

2:4.15.13+dfsg-0ubuntu0.20.04.4~ppa1 includes the fix from 2:4.15.13+dfsg-0ubuntu0.20.04.3.

You can click on the package name in this[1] view and it will show two changelog entries: mine, and the previous one from the security team.

1. https://launchpad.net/~ahasenack/+archive/ubuntu/samba-kb5028166/+packages