I couldn't upgrade the version for my n900 so I was one of the lucky that could transfer my maemo licence to android licence. You could always try to mail them, but it seems that they don't approve the movement anymore.
How long should the license be valid, in case you transfer it to Android? Probably not for ever?
It's forever(If sygic let you transfer), but sygic will probably move on to another android version in future and then its probably over. But for now, I got all the android updates.
Well, the sygic maps are encrypted and not retro compatible.
There was a tool to decode these maps allowing to read the data inside... and the archives inside are very similar between versions...
After this, no more progress.