How are Steam updates handled?

How does Steam handle updates coming from Unity builds?

I've read some old posts on Reddit about how Steam uses diffs (similar to version control). But I've also read posts about people using AssetBundles. Obviously, being able to just rebuild the entire game and upload that with Steam figuring out what new files need to be downloaded would be the most convenient.

Any ideas? Any Unity devs using Steam that could provide some insight?

 

Any package that has a later date modified will be applied in the update.

 

Just for clarification, by package you mean the folder you upload to steam with the new Windows build in it?

Will users only download the files in that build that are different than the previously uploaded build?

 

Upload the entire project/depot to Steam for each update. Steam will automatically create a binary chunked version of that depot and feed users only the changed chunks. Meaning the updates are typically small for code (likely only a chunk or two).

 

That's awesome! Thanks for the response

 

I have noticed that the bigger the game get the larger the required download is even if its just a code change.

edit: We havent bothered with asset packages etc just yet, which might help Steam make better update chunks.

This was just a small update yet 4.1 gigs to download