I had issues with Nvidia 8600m and kernel 5 and I want to go to a stable setup.
Which kernel is LTS and works with Ubuntu 18.04 and where do I download it from?
Ubuntu 18.04 LTS (installed via Ubuntu 18.04 LTS or Ubuntu 18.04.1 LTS ISOs/media) came with the 4.15 kernel, with the option to use the HWE kernel when it came out.
Ubuntu 18.04 LTS installed with 18.04.2 or later ISOs/media (or prior installations with HWE kernel option enabled) use the 18.10, 19.04, 19.10 and 20.04 kernels so which kernel depends on whether or not you have HWE enabled.
https://wiki.ubuntu.com/Kernel/Support
For more detail on HWE (hardware enablement stack) kernels please see
https://wiki.ubuntu.com/Kernel/LTSEnablementStack
You can download kernels from https://kernel.ubuntu.com/~kernel-ppa/mainline/ (both patches & deb's) though you'll already have the kernels installed; so I'd stick to default kernels (with/without HWE) to ensure they get patched automatically, but assuming you want to download for testing or other, you'll find them here.
