The database migration to 0.19.4 failed, because the database schema doesn't align with the state the migrations want. The reason is probably because it didn't restore correctly from a previous backup, but I don't actually know the cause.

I thought I could create a new database with a correct schema and then import the data from the currrent database into the new one. This might still be possible, but it simply takes too long and it has gotten too late for me(03:00 in the night).

I will look into a fix for the migration and when I have a fix I will announce a new date for the upgrade to 0.19.4.