tldr: If you require hardware support offered by the Linux 5.x kernel then I suggest you remain on 6.8.0-rc7 and wait until 6.9.0-rc1 is published before upgrading.
The "unexpected GSO type" bug is looking to be a show stopper for Unraid 6.8 using Linux kernel 5.3 or 5.4 kernel. We can get it to happen easily and quickly simply by having any VM running and then also start a docker App where Network Type has been set to "Custom : br0" (in my case) and I've set a static IP for the container or toggle between setting static IP and letting docker dhcp assign one. There are probably a lot of users waiting for a stable release who will see this issue, and therefore, I don't think we can publish with this bug.
The bug does not occur with any 4.19.x or 4.20.x Linux kernel; but does occur with all kernels starting with 5.0. This implies the bug was introduced with some code change in the initial 5.0 kernel. The problem is that we are not certain where to report the bug; it could be a kernel issue or a docker issue. Of course, it could also be something we are doing wrong, since this issue is not reported in any other distro AFAIK. We are continuing investigation and putting together a report to submit either to kernel mailing list or as a docker issue.
In any case, an actual fix will probably take quite a bit more time, especially since we are heading into the holidays. Therefore this is what we plan to do:
For 6.8: revert kernel to 4.19.87 and publish 6.8.0-rc8. Those currently running stable (6.7.2) will see no loss of functionality because that release is also on 4.19 kernel. Hopefully this will be last or next to last -rc and then we can publish 6.8 stable. Note: we cannot revert to 4.20 kernel because that kernel is EOL and has not had any updates in months.
For 6.9: as soon as 6.8 stable is published we'll release 6.9.0-rc1 on next release branch. This will be exactly the same as 6.8 except that we'll update to latest 5.4 kernel (and "unexpected GSO type" bug will be back). We will use the next branch to try and solve this bug.
New features, such as multiple pools, will be integrated into 6.10 release, which is current work-in-progress.
We'll wait a day or two to publish 6.8-rc8 with reverted kernel in hopes those affected will see this post first.