Context is important. It’s possible that the software is distributed without any warning like that and that the termination of the support contract is done without citing the redistribution of previous versions as a reason.
OTOH if the customers could prove that there’s widespread knowledge of the retaliatory termination that could be equivalent to a (non-written) restriction that is indeed incompatible with the GPL
The warning is in the agreement every customer (and free developer account) signs to obtain access. They also mention they could sue you, although I think it is unrealistic they would do so just for redistribution.
I think it depends on whether it’s considered an additional restriction on the recipient’s right to redistribute the software.
Saying, “you can redistribute the software but you will face _____ penalty” seems like a gray area to me.
Context is important. It’s possible that the software is distributed without any warning like that and that the termination of the support contract is done without citing the redistribution of previous versions as a reason. OTOH if the customers could prove that there’s widespread knowledge of the retaliatory termination that could be equivalent to a (non-written) restriction that is indeed incompatible with the GPL
The warning is in the agreement every customer (and free developer account) signs to obtain access. They also mention they could sue you, although I think it is unrealistic they would do so just for redistribution.