Just upgraded to v17.4 (9f7bd15) and can no longer find in Settings the function 'Mark similar articles as read.' The other day Fox said he wasn't happy about it. Has he decided to kill the cripple?
you sure you have the trgm plugin enabled? i don't remember changing anything there
Solved. For some reason I had the af_psql_trgm plugin disabled. One explanation I can find is that I've just upgraded PostgreSQL, the trigram extension must have got deleted, and the plugin got disabled.