anybody know?

It would be v4.13, not 4.12 which had a bug which was quickly fixed.

There's no reason not to use it - it's available from the SETI site amongst others, and Carl encouraged people to upgrade if they were having problems. But upgrading also produced its own set of difficulties for some. So, if <i>it ain't broke, don't fix it</i>, may be the prudent course, though quite a lot of us seem to have upgraded without problems. You will need to if running other projects such as SETI.

I suspect the team may be waiting for the next release, as there were a number of things that 4.13 didn't fix.