Yes, it was strongly rumored/suspected during the pre-season that this would be the last one due to some very strong evidence, but now it's official.

Merlin not becoming an equal is going to be the thing that I mourn the most out of this entire stupid show. I'm not sure I realized just how strongly I was waiting for and expecting that until now. I knew we'd probably have to wait until the last season, but now that we're most of the way through the last season and it's still not happening.... :-(