I haven't had reliability problems, but I do find it annoying that if I don't update my app frequently enough, they just cut communications entirely. That is, I don't get notifications that I've received new messages anymore. I usually find out about this when someone emails me to say they've sent me a message on Signal, but I've not responded.
Instead of silently failing, I wish they would pop up a notification that says "Your version of Signal is now out-of-date, and you will not receive new messages until you update."
Instead of silently failing, I wish they would pop up a notification that says "Your version of Signal is now out-of-date, and you will not receive new messages until you update."