There's not a current vs old version...just different profiles...they are all current...
well, there are indeed many versions. but yes, likely all of them still in use.
my own experience, all new TV shows in hevc CANNOT be played on old boxes - that's why i call them "current" version.
On April 13, 2013, HEVC/H.265 was approved as an ITU-T standard.[23][24][25] The standard was formally published by the ITU-T on June 7, 2013 and by the ISO/IEC on November 25, 2013.[7][6]
On July 11, 2014, MPEG announced that the 2nd edition of HEVC will contain three recently completed extensions which are the multiview extensions (MV-HEVC), the range extensions (RExt), and the scalability extensions (SHVC).[26]
On October 29, 2014, HEVC/H.265 version 2 was approved as an ITU-T standard.[27][28][29] It was then formally published on January 12, 2015.[7]
On April 29, 2015, HEVC/H.265 version 3 was approved as an ITU-T standard.[30][31][32]
On June 3, 2016, HEVC/H.265 version 4 was consented in the ITU-T and was not approved during a vote in October 2016.[33][34]
On December 22, 2016, HEVC/H.265 version 4 was approved as an ITU-T standard.[35][36]
https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding