I know that the big distros like Red Hat/Fedora, Ubuntu, and OpenSUSE have been rolling out updates as some of our clients were getting notifications.
As for Solus, since it is a manual method to enable secure boot with the solus-enroll-me.cer so if you are not using Windows on the same system the impact would be minimal. The devs will essentially have to get a shim update signed by the newer Microsoft UEFI CA for Solus and I do no know where the progress is on that end.
Why Microsoft is allowed to be the CA is beyond me. Essentially get to self sign their own and charge others.
