Re: Some Mail-Clients put a "RE" or "AW" or "Antwort" or whatever in front of the subject.
"Re:", "Aw:", "Fwd:", "Отв:", and also "Re[2]:", "Fwd[10]:" and their combinations are removed / ignored when comparing subjects.
"Antwort:" is just crazy
Re: attached a screenshot how it lokls in mutt
Umm... Yep, different subjects.
Re: It seems that when you accept an email calendar invite on EWS exchange account
Will take a look, thanks.