Like others have said here I'd advise against it. It will absolutely put you in a position of weakness in the future because everywhere you go you'll have to b

Like others have said here I'd advise against it. It will absolutely put you in a position of weakness in the future because everywhere you go you'll have to be like "I was using Delphi in my last job ... but believe me I'm good and I know modern stuff too!". The exception I would say is if you are some kind of big shot developer with a big proven public track record that has people offering him jobs every day and so on so you just don't have the worry of having to prove yourself to others in the future. In that case ask for a super high salary and go for it if you feel it's right.