Hi, Since commit e24c9a9265af40781fa27b5de11dd5b78925c5be to wireguard-linux-compat with a fix for some Ubuntu versions, we are experiencing a problem with some older, but still LTS, versions of Ubuntu 16.04: older kernels 4.4.0-148, 4.4.0-166 fail to build with wireguard 1.0.20200611
So, any system running an (or still having an installed) "older" kernel and doing an apt upgrade to install wireguard 1.0.20200611 would fail during the wireguard dkms step, while trying to build wireguard for all the kernels available. The problem gets more problematic when a newer kernel 4.4.0-184 gets installed with the same apt upgrade: then, trying to downgrade wireguard also fails; none of the 1.0.20200611 or 1.0.20200520 versions work anymore with this combination of old/new kernels... To recap : # wireguard 1.0.20200520 - ok with kernels 4.4.0-148, 4.4.0-166 - fails with kernel 4.4.0-184 # wireguard 1.0.20200611 - fails with kernels 4.4.0-148, 4.4.0-166 - ok with kernel 4.4.0-184 (nb: we see it now with -184 but it could have started with an earlier version) We could partially fix this by manually getting each deb/src and doing dkms install: dkms install wireguard/1.0.20200520 -k 4.4.0-148-generic dkms install wireguard/1.0.20200611 -k 4.4.0-184-generic ... But apt upgrade is still broken. While we could boot onto the newer kernel and remove the older ones to get rid of the problem, this situation would prevent from having a "previous working" kernel on the system, which is not very safe. Could there be a fix for this made to wireguard-linux-compat for those versions? Best regards, Greg