First, the Xbox One's long-awaited first patch will arrive today, community lead Marcin Momot said on Twitter. "Sorry for the wait!" he wrote. This patch, 1.03, will lock the game's frame rate at 30fps. This should clear up the somewhat annoying stuttering issues some players (including myself) have experienced.
It is unclear if the 30fps lock will be optional. We've followed up with CD Projekt Red to find out.
Presumably, the patch will make further tweaks, though CD Projekt Red has not published a changelog. Last week, the developer released an update for the PlayStation 4 edition that included a range of visual tweaks and bug fixes. We would imagine these would also be rolled into the Xbox One patch.
In addition, CD Projekt Red has announced plans to fix the XP bug that came to light earlier this week. A new patch to clear up this issue, 1.04, will arrive on Monday, June 1 for PC. The update will be deployed for Xbox One and PlayStation 4 "in the following days," Momot explained in the game's forums.
"First of all, it doesn't impact the game balance in any significant way," Momot said. "Also, you will be able to finish the game with your character achieving a level within the threshold we had in mind when we designed the game."
CD Projekt Red previously explained that if you're completing quests and not being rewarded with XP, it might simply be that you're undertaking ones that are too low-level for you.
Finally, Momot promised that CD Projekt Red "won't stop working" on making further improvements and tweaks for The Witcher 3. Additional patches are planned for the "near future."