Locking Posts
Although I can’t state for sure, I think this is automated that if a post hasn’t had any activity for a while it is automatically locked. At one time there was a really bad problem on this forum with spam accounts so some precautions were put in place. I’m cant say for sure if these are still applicable (maybe @milipili or @donho can decide if these are still relevant). I agree that even if some posts seem “old” they can still be relevant for discussion.
Closing Threads Stating a thread is too old.
I’m not sure I recall any of these happening. (If so it is incredibly infrequent). Care to point out some examples?