People are always temponary testers. When a new beta come out, people will need to apply again. If you have been betatester before, the there is a much bigger chance of getting accepted, yes.
But like Patchou said, he always deletes the list of tester mailadresses after a beta is over, so there is no way for him to reach all old testers again with a new beta. For example DXtremz has been tester for a long time, but he didn't recieve the 3.50 beta because he didn't send an email whe Patchou requested it in his topic... Maybe Patchou does otherwise this time, but this is how it always went with other versions.
But sure there are some testers which will be asked to test by Patchou, even when they didn't apply
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