HOW TO REVERT BACK TO NIS v20.x from v21.x ? don't like version 21.0.1.3

How do I revert back to Version 20.4.0.40 ?  using version 21.0.1.3 on my other computer and don't like it at all.  It constantly keeps asking me if I want to use the Cloud - I say no keep local and next time it pops up again.  want my old version back!! thanks for help!