When I upgraded it made the switch from MySQL to MariaDB, which is said to be a drop-in replacement. I was skeptical.
TTRSS stopped updating, so I ran some of the command-line tools to see what errors there were.
Exception while creating PDO object:could not find driver
Hmmmm. This is what fixed the initial errors:
sudo apt-get install install php-mysqlnd
Let’s run the tools again:
Tiny Tiny RSS was unable to start properly. This usually means a misconfiguration or an incomplete upgrade. Please fix errors indicated by the following messages: * PHP support for mbstring functions is required but was not found. * PHP support for DOMDocument is required, but was not found.
after some googling it turns out I needed a couple of php7-specific packages:
sudo apt-get install php7.0-mbstringsudo apt-get install php7.0-xml