There be Problems!!!
I did the 18.10 to 19.04 upgrade this morning (4/19) after updates percolated to .es. (The 18.10 was a hardly-used clean install from a few months back.)
Update appears to be OK, but following messages were displayed:
Could not install "linux-image-5.0.0-13-generic"
The upgrade will continue but the "linux-image-5.0.0-13-generic" package may not be in a working state. Please consider submitting a bug report about it.
trigger looping, abandoned
Could not install the upgrades
The upgrade has aborted. Your system could be in an unusable state. A recovery will run now (dpkg-configure --a)
The upgrade has completed but there were errors duiring the upgrade process.
So I ran 'sudo dpkg --configure -a' before reboot, as recommended here 1825420
System Monitor reports Release 19.04 and 5.0.0-13-generic x86_64. It initially all seems OK, but glad it wasn't my daily driver