After being rather slack and not running updates for a while (there were quite a few ready) I clicked on the "Update to latest version now" yesterday. It did the first few, and then stopped.
The web UI shows
Current firmware version: 9.210-20
Latest available firmware version: 9.303-2
Todays up2date log looks like
UTM up2date - Pastebin.com
I think the key part is as below, but I'm not sure
id="371J" severity="error" sys="system" sub="up2date" name="Fatal: Version conflict: required version: 9.209008 current version: 9.210020" status="failed" action="install" package="sys"
This thread was automatically locked due to age.
