Bethesda published a letter to fans today thanking them for supporting Fallout 4. They also outlined their plans for patching the game now that it's available worldwide.
In the letter, Bethesda says that Fallout 4 patches will be rolled out on PC first, just as they were for Skyrim:
Our process for updating the game will include releasing a beta patch on Steam, followed by full release on PC, then release on the consoles. This process has worked well for us in the past and allows us to get more fixes out faster. Expect to see more updates, that are smaller and more frequent, than a few big ones. This allows us to make sure each fix is working right, as any change can have unintentional side effects in a game this huge.
Bethesda says that the first beta patch will be available through Steam next week. They didn't provide a timeline for rolling out the update to other platforms.
We don't know what exactly the patch will fix yet. Bethesda merely states in the letter that there are always "unintentional consequences" when designing an open-world game with so many pieces.
Given the scale and complexity of the systems at work, especially when allowing you to build your own settlements, we're happy that Fallout 4 is our most robust and solid release ever, and we'd like to thank our amazing QA staff who worked as hard as anyone to break the game so we could fix it during development. But a hundred testers will never replicate the many millions playing the game now, and we're hard at work addressing the top issues.
Bethesda said in the past that post-launch patches will also bring new features. We don't know what these features will be but they could be substantial. Skyrim received a bunch of major improvements after launch including mounted combat and a legendary difficulty setting.
The biggest free update of all, though, will be the release of the Fallout 4 Creation Kit early next year. The Creation Kit is the same toolset that Bethesda used to create Fallout 4 and should be a huge boon to the community. Modders have already made some impressive creations thus far so it's exciting to think of what they can make with the official tools at their disposal. While the Creation Kit will only be available on PC, modders will be able to share their creations with PS4 and Xbox One owners.
While working on these free patches, Bethesda will also be developing paid DLC. All of these add-ons will be included with the $30 Season Pass.