My saved messages that IÂ’ve had since 2013 and 2014 disappeared. Not quite sure when, but I think it was sometime in the last week or two. The 2015 and younger messages werenÂ’t affected though, so is this a bug or did you just delete all messages older than three years Eve?

I don't think messages 3 years and older are deleted; I still have messages saved from 2014 which, now, are over 4 years old