Default file save format changed from ts to mkv
I just spotted this one after a couple of recordings with 3.9.1838. Annoyingly ProjectX, which I usually use to process the recordings, won't touch them. When I first started using tvheadend mkv was the default format. I changed it to ts, which became default a few months back. I guess the latest upgrade saw that I had ts there and assumed that I was using the default value. I'm not sure how you'd differentiate between a default value and a selected one in the config files without a lot of tedious and largely unnecessary rewriting so I'm just giving a heads up to anyone interested.
I opened a bug report to the effect that recording profiles were updated going from 1743 to 1777, and my selection "pass through" was replaced by matroska. https://tvheadend.org/issues/2364
In the recording profiles (configuration-recordings-DVR profiles) you should be able to change your stream profile back to "pass."
I left it at mkv because I want to see how stable the mkv writer is these days. I am impressed, half a year ago it was impossible to write 2 mkv files simultaneously, now they work fine.