OpenSource to Commercial Qt?

[pherthyl]

There's two issues here. One is the legal one which jpn pointed out. You're not allowed to start a project with the open source version of Qt and then buy the commercial version later.

Does it mean that if I have developed a project with the open source lib,it is too late, thus I must die?

My personal feeling is that if you started some experiments with the open source version, but havent released the program yet, and now you want to buy the commercial version for it, then do. You win and trolltech gets another license sale. If you adhere so strictly to the rules then you lose and trolltech loses a sale too.
I know no one is going to agree with me on that point though. Don't take it as an endorsement, I'm just stating a personal opinion.

The other issue is the technical one, and it doesn't exist. The commercial version is 100% compatible with the open source version, so "porting" is just a recompile of your program.