Check In Versions on Update 20

I have installed SP20 in my DEV env. and I am still checking in my versions outside OMW.
Just to tell you, cause someone told that this would not be possible.

That is correct. JDE has not removed this functionality they have just made it work with OMW. If you did not have rights to check in a version through OMW you would not be able to check in the versions through BV.