Last night my ageing jessie stretched herself, and – whoa! – ttrss flies. I guess that’s the combined effect of PHP going from 5.6 to 7.0, PostgreSQL from 9.4 to 9.6, and your, guys, masterful coding.
Welcome to the XXIst century!
Don't forget to do the post-upgrade on your psql. I did the same thing a couple weeks ago.