Kudos for having constexpr in this release. In the previous post said that constexpr wouldn't be completely ready in 2015. Great to see that wasn't the case after all!
It was a close call, but we got it done just in time. (It took a month and a half to constexprize the STL. I went through 84 shelveset revisions, which would be like feature branch checkins in git, and that's not counting the numerous compiler fixes that Tanveer, our front-end dev working on constexpr, checked in.)
Great job guys! Thanks for the effort! constexpr is an useful feature that some library devs have been waiting for.