A post to the Overwatch Forums from Blizzard game director Jeff Kaplan discusses how things will change between the end of open beta testing on May 9th and the official launch of the multiplayer shooter on May 24th (thanks VG247). Word is the version being played now is essentially the same as the release version, with the exception of competitive mode, which is getting a lot of changes at the moment. A previous post notes the competitive mode will not be live for the game's launch, saying: "Our plan is to bring back a newly re-designed version of Competitive Play sometime after Overwatch launches." Word is they are already working on "a TON" of free content to release after the game:

Yes. The version you are playing now is what will go live at launch (there will be some bug fixes etc...). We also have Competitive Play, which was a feature that was live in Closed Beta. We removed it from Open Beta because we received a ton of great feedback on how to improve the system. We had a tough choice. It would have been awesome to have the feature in for Open Beta and Launch. But we felt like we could really improve on some things so we opted to have the feature come out shortly after launch. We're hoping that our efforts in the Closed Beta to try to get things done quickly and at high quality aren't lost on our community -- but we also never want to sacrifice the quality of the game by putting something live that isn't up to our standards.

We're also working on a TON of post-launch features and content. It's going to be a pretty amazing summer...