Colobot 2 is a next milestone after Colobot: Gold Edition. It is supposed to be a sequel of the original game, created fully by TerranovaTeam this time. The plan is to use the fully refactored engine running Colobot: Gold Edition to build the game.
Currently, TerranovaTeam does not like to talk about this project, because development of it will start long in the future. Any details about it do not exist or are not official and certain.