It appears as if they are modernizing the T-55 type tank. The square boxes you see on the outside of the tank are Iranian design copies of the Russian Konkakt-5. It is an explosive reactive armor. You will also notice a 105mm gun and a BMP-2 being worked on.
Other sources have said that they are taking the T-55 body and modernizing the tank fleet into T-72s.
These pictures are not recent and have been around for over a year now