It's currently heading out to G8 units purchased from both Sprint and Verizon. The former carrier actually started the rollout earlier this month, while Big Red followed today.
Verizon's version of the update is G820UM20a, and it includes the December 2019 security patch level. There are additional goodies tacked on top by LG, make sure you visit the first source linked below for the full changelog.
As always, these rollouts are likely to be staged, so don't fret if you haven't yet received an update notification, it should arrive within the next few days. If you're impatient, you can always try to manually check for the update through your phone's Settings menu. That may or may not get you ahead in line, but it doesn't hurt to try.