Next update v3 will be live very soon™, but it packs few core changes so it’s impossible to install it on top of v2.1 or below without severe damage to constructions you made and messing up content inside “Uniblocks” folder. Please, backup your project before update and remove Uniblocks from the project before installing v3 - fresh installation is the way to go in this case.
Feel free to contact me in case there are substantial amount of custom made buildings from v2.1 that needs transition to v3.