A "preview version" refers to an early release or a sample of a product or software that allows people to see or try it before its final version is officially released. Full definition
Some early preview version of the game have gotten early reviews. (mypotatogames.com)
While the general public is receiving access to Android O beta for the first time, Android developers have had access to the first developer preview version for weeks now. (nashvillechatterclass.com)
We went hands - on with the new preview version to test them out. (businessinsider.my)