Comment 2 for bug 1851447

The problem is rather the opposite; the aufs in the kernel is newer than the synced aufs-tools. And I just recently found out that aufs for 5.x kernels is hosted in a different git repository, which explains why we haven't been seeing any tags for 5.x kernels (and thus the version is still 4.x-rcN).

For focal then we likely need to update aufs-tools from https://github.com/sfjro/aufs5-standalone
and update aufs-tools every time we update the kernel support. However, if the tools and kernel support really are version locked as this build error implies, that seems to pose a problem for hwe kernels.