The second major version of Geometry Dash is Update 2.0. It was released on August 26, 2015 and added major features like new levels, the robot gamemode, teleportation portals, and account/social systems.

What it added

  • New levels: Geometrical Dominator and Deadlocked.
  • New gameplay features like robot mode and teleportation portals.
  • New account features such as friending, following, messaging, and user coins.

If you meant something else

If by “2nd version” you meant the second update after launch rather than the second major release , that is still generally referred to as 2.0 in the community and update history.

TL;DR: the answer is Geometry Dash 2.0.