Maybe there is a thread already but let me start one. I just updated an old multiplayer VR project from 2021.3 to 6. Smooth sailing so far but there are difficulties on the horizon as deprecated libraries/classes are showing up. It doesn’t currently build but other than that things are cool.
Figured I could use this topic for when I get stuck.
ok, that made my day
Hah, hah. Part of this is due to my using Odin (which I love) that is warning me about the deprecated parts. I could override the settings but for now I want to see about getting a clean, warning-less build.
I definitely need to attend to interaction toolkit-related changes. https://www.youtube.com/watch?v=Seghspj6kow
And if anyone else is migrating a VR app/game please feel free to join in and share issue and solutions. Solutions mostly I hope 
mind if i ask why you migrate the app? what has unity6 that you need for your game?
I hope there are lots of questions (and answers) people need information to make decisions. In my case I do all this development for fun and learning. I tend to like to keep projects reasonably up-to-date. There are typically bug fixes and often security fixes included. There are also any number of new features that can make development easier and more likely to work in newer environments (and with newer headsets).
In my specific case I was working on a version of the interaction toolkit that was slightly patched to work around a recognized bug. With any luck the work around is no longer needed (there are new components) in the 3.0 version of the toolkit.
If those aren’t enough reasons… eventually all the tutorials / docs and support info will be relevant to Unity 6 and anything that remains buggy in older versions will be met with “that’s been fixed in 6”.
I couldn’t quite get my head around the new components so for now I started a new test project and immediately I can see it add the components that are needed. This alone should make my conversion easier. I have one of these and it has been replaced with one of those becomes more obvious.
People really should not do normal upgrades to Unity 6, make a new project, import anything from the asset store, and then transfer your remaining assets.
Keeping old project settings, and the old package manifest will absolutely screw you.
There’s so much different internally a simple upgrade will likely be a problem. Best just configure your project from the defaults.
When i first tested Unity 6 doing a normal upgrade caused a TON of problems, then I did the process above and it was MUCH better.
I think that is very good advice. I have in the past regenerated projects using newer versions and it not only gets a clean project but you learn about the new system and question some of the stuff in the old system.
I’ve also had tooling that somehow got hosed, magically work again after moving all the assets to a clean project.
Don’t forget to delete the library folder (while the project is not open) and also do a “reimport all assets”. Those two tasks refresh any possibly outdated metadatafiles.