| I think this is less technical and more 'political' / contractual, as it used to be: > This is to certify that Oracle Corporation has entered into a Trademark License Agreement with X/Open Company Limited in accordance with which the following are registered under the X/Open Brand Program. * https://web.archive.org/web/20191022053203/https://www.openg... * https://www.opengroup.org/openbrand/register/brand3642.htm An August 2018 tweet: > We are pleased to announce that Oracle Corporation has achieved certification to the UNIX V7 Product Standard for: Oracle Solaris 11.4 Operating System and later on SPARC-based and X86 based platforms. For more information: http://ow.ly/8fT830lBjfu #UNIX * https://twitter.com/theopengroup/status/1034785507610447872 There's a renewal process: * https://www.opengroup.org/openbrand/docs/UNIXV7_Certificatio... Oracle did not bother renewing in April 2019: > Solaris supports SPARC and x86-64 workstations and servers from Oracle and other vendors. Solaris was registered as compliant with UNIX 03 until 29 April 2019.[6][7][8] * https://en.wikipedia.org/wiki/Oracle_Solaris |