Think its going to be the last one , Dave told press the last tour that he was "starting to feel it" and that they can not keep performing like this forever.
Good for them stopping when your not falling apart (for the second time , haha)
I doubt this will be the last one. They've said otherwise in recent press for the new album. I don't think they would ever announce it, they would just stop. They would certainly never put a song goodbye as the meaning last album, they are not that obvious - far from it.
Regardless, really looking forward to the album and tour. I've heard good things from people who have heard the new album. Even that one of Dave's songs is one of the best on the album.