Hi Gunther,
after updating to LRT 5.7.1, the program said "not licenced"!?
So I opened the licence-activation dialog and reactivated my licence, now it works again.
Is this a bug or a feature?

Greetings, Kurt

Normally, the license gets preserved on updates (99.9%). But in very rare cases you might have to reactivate it. Since you usually have your license in your email, that's no problem at all.