Horizons Vanilla user here.

[Puzzykat011]

If I upgrade to 2.2 when it arrives. Will it include everything beforehand.... Like engineers?

 

[Dregory The Crow]

You upgrade to whole season 2 Horizons: 2.1 Engineers, 2.2 Guardians, 2.3 and 2.4.

 

[Ian Phillips]

When you buy a season of upgrades (Horizons) it includes every upgrade for the whole season, so 5 major upgrades.

Short answer = Yes

 

[Puzzykat011]

Cool thanks