According to Ars, they got confirmation from Oracle that they will not be going ahead with Solaris 12 as planned. Solaris 12 has been canceled and wiped off their roadmap. Oracle is said to be working on a "Solaris.next", but no details yet. This "Solaris.next" is also reportedly the only planned Solaris update through 2021.
More details from Oracle on the demise of Solaris is supposedly coming later today.