- Ubuntu Focal 20.04 LTS: native built-in
- Ubuntu Eoan 19.10: native built-in
- Ubuntu Bionic 18.04 LTS: native built-in
- Ubuntu Xenial 16.04 LTS: dkms :(
- Ubuntu Trusty 14.04 LTS: dkms :(
- Debian: native built-in
- Fedora: native built-in
- Mageia: native built-in
- Arch: native built-in
- OpenSUSE: native built-in
- SUSE Linux Enterprise: native built-in
- Alpine: native built-in
- Gentoo: native built-in
- Exherbo: native built-in
- NixOS: native built-in
- RHEL/CentOS: dkms and elrepo kmod :(
- Void: native built-in
- Adélie: native built-in
- Source Mage: native built-in
- Buildroot: native built-in
The rule of thumb here is: distros with kernel ≥ 5.6 have it native built-in, plus a few distros that have backported it, like Ubuntu, Debian, and SUSE. I'm in the process of working with other distros to get it backported; we'll see if I'm successful. I'm also maintaining a 5.4.y backport for distros who ship this LTS kernel (like Oracle's UEK), to make backporting it easier: <https://git.zx2c4.com/wireguard-linux/log/?h=backport-5.4.y>. There are instructions for each distro on <https://www.wireguard.com/install/>.
If you're presently having "update troubles", make sure you're using the latest variant of any of the "native built-in" distros written above.