I've run some tests on Spigot 1.16.1 and found no errors so far. No changes were necessary for Boost to run in 1.16.

Other work has been progressing and two new features are added in this update:

• Place holders, registered with PlaceholderAPI.
  See the supported place holders here: https://github.com/pmme/Boost/wiki/Placeholders

• Boosting cooldown
  There's now a configurable cooldown delay between boost hits. The default is 10 ticks, which is 1/2 a second. You can configure whatever you find suits you. A setting of 0 disables this feature.
  Use "/boost setcooldown <ticks>" to set the cooldown in server ticks.