@gnasher729 Personally (different trans person here), I'd definitely prefer if you said something like "Hi Matthew, I think we knew each other in school" and then saying something identifying either about yourself or about your relationship that doesn't involve the name. I wouldn't particularly be
offended if you said the old name in that context, but I definitely wouldn't
like it – and also it only helps
you remember the interaction, it gives nothing extra to the person you're talking to. —
anon 1 min ago