I seem to recall that when

Usage Stats

was first introduced, there was some verbiage about it not being turned on by default for Upgrades, just new installs. I can't seem to find that right now, is this still correct?

there was some verbiage about it not being turned on by default for Upgrades, just new installs.

Yep! This is correct. Anonymous usage stats were introduced in Fleet 4.0.0. The Fleet 4.0.0 changelog here specifies the above: https://github.com/fleetdm/fleet/releases/v4.0.0