Welp.. essentially loosing support for netcup vServers would be very impactful for us. We´d have to convince a lot of customers to move to rServers or another hosting service, not even mentioning our time spent on migrating their servers.
I guess this is one of those problems where nobody is to blame - I get netcup´s stance, but cooking up two cloudron versions every release circle doesn´t sound practical either.
I´ll send an email to netcup customer support, maybe they can be convinced to add AVX support if enough of us are complaining.