i need the Revisions feature
i searched for it, all topics said that it is available in K2 v3 only
where to find this release and is it safe to use it ?

because i saw this in 2014 : The first public beta release of K2 version 3 is finally here!

It can be used in dev sites, but in production sites you would need some coding knowledge should you encounter any issues eg: the frontend is not finalised.

Is final release coming out soon?

Soon, but I cannot tell you for sure how soon.
You can test the beta version here: github.com/joomlaworks/k2-v3-dev-build

If you are looking for a more complete solution for the frontend, and some tweaks as well, take a look at this repo as well:
github.com/kricore/Advanced-templating-with-K2