Is there a way to do auto-patch functionality of games made in Unity (PC/Mac)? For example, after releasing the game, we’d like it to be able to check for updates (remotely), download and then update the actual game (without reinstalling).
No, sadly not. You have to either reinstall the whole game or use a binary diff tool to create the patch.
I have never used any but here is an example Visual Patch 3.8 - Indigo Rose Software
This is an old post but I figure I would give some hope to the future generations ;). I use a binary diff tool like @Sarper Soher said but I also give a guide on how to make your own patching system (code included) here:
Hope this helps somebody else out in the future.
Update 10/27/2016:
Just found an absolutly amazing tool that works flawlessly for windows. Check it out at their github repository:
Their documentation on how to use it is fantastic. They claim that this will work with comparing remote files as well. Even if it doesn’t uploading the “signature” files and “delta” files for each patch update could be the answer.