In news that isn't especially surprising, it seems as though the Sony A mount is finally dead.
It has been six years since Sony last released an A mount camera and seven years since they last released an A mount lens, and it seems like the unique DSLT (digital single lens translucent) line is finally officially done. Sony Japan has listed all all A mount lenses as "discontinued," and given the lack of development in the last few years, it seems safe to assume the line is finished.
Even with the lack of development, the news is not particularly surprising. Sony was unlikely to continue to support two distinct mounts, and the technology that drove the DSLT design, while quite interesting, was rendered essentially obsolete by the advent of on-sensor phase-detection autofocus. Before that, the use of the pellicle mirror (which actually was not translucent) in the DSLT design allowed incoming light to be split into two pathways, one going to a phase detection autofocus sensor, and the other to the sensor, which also fed the electronic viewfinder.
The downside of this system over a modern on-sensor phase detection system, besides the increased complexity, was a loss of about a half-stop of light reaching the sensor, as some of it had to be used for the autofocus. Nonetheless, the A mount line was quite popular and became rather sophisticated near the end of its run. While Sony has not issued an official statement on its demise, it seems safe to assume that this is the end of the line. The A mount far predates Sony's time with it, having been introduced by Minolta in 1985.