We'll be switching the LTS kernel to 5.15 in the coming sync (the current plan is to skip this Friday's sync for additional testing time). The LTS kernel will be identical to what is currently the current kernel so we highly recommend you boot into the current kernel and identify any issues so that we can resolve them before the sync. Our goal is to try to get as much hardware as possible working with linux-lts so we don't have to leave anyone behind, but ultimately the former 4.14 kernel is holding us back in several areas and we are going to upgrade past it.
If you do encounter major issues with 5.15 you can continue to temporarily boot into 4.14 and so long as you keep booting into 4.14 the system kernel manager will keep that version installed. However in several months we will be upgrading systemd to v251 which has a hard dependency on newer kernels, at that time if you are still on 4.14 your system will not boot.
You can post your issues with 5.15 here or you can reply in this thread and we'll do our best to copy it into that tracking meta-issue. If you already have an issue on dev.getsol.us please link it and we'll get it added to the meta-issue.
linux-current users, we are currently testing 6.0 and would like to get it in ASAP however we want to ensure that the linux-lts users have a good experience with 5.15 before we fully switch our attention to 6.0. I don't really expect 6.0 to go in before the next sync, but hopefully it can make the following one. Thank you for your continued patience, future kernels will be delivered much faster in the future once we have LTS squared away (as LTS serves as our haven for users who encounter issues with linux-current).