I use teslafi. Just installed 17.28.
Oddly, it caught 17.28.27... and then 3 minutes later when the upgrade was finished, it changed to 2017.28 c528869
So, I suspect they are actually the same (or rather, 17.28.27 is the base update, and the c528869 is a small delta patch to fix something minor that is applied at the end of the update process).
Is anyone actually running 17.28.27?