$ apt-cache policy rsync | grep Installed
Installed: 3.4.1+ds1-7ubuntu0.2
$ sudo apt-mark hold rsync
rsync set on hold.As usual, Ubuntu backported fixes and didn't upgrade to a new version. Whether or not they also backported regressions in edge cases that afflict the latest rsync, I don't know. Pinning the Ubuntu package may prevent getting further regressions, but is preventing you getting any future such backported security fixes.
This is a terrible argument; I didn't need to have had secrets exfiltrated before applying row-hammer mitigations. If rsync is the cornerstone of my backup strategy, and has been for years, I need to trust that on its correctness, and for it to not lose my data. If I wait until I "face any actual bugs or regressions" - that will be far too late.
Stability is another issue not discussed. If the error rate holds steady, but number of significant PRs merged per release goes up from 5 to 200, that would be huge net-negative for my use case.
I didn't have the time to actually think about any "arguments" at all tbh it's just a knee jerk reaction as I get ready to log off for the weekend. Not actually looking to argument for or against your post at all lol.