Unity3d Does opening a scene from a previous version upgrade the entire project?

Question

I'm fairly new to Unity but have a lot of experience with web and flash game dev so feel very comfortable with the tools etc. I have been using the 4.6 trial up to this point with no problems, now my employer wants to make some changes to an older git version controlled project. I looked up how to run 3.5.7 alongside 4.6 and after installing can open a new project just fine. When trying to open the older file in 3.5.7f6 I receive the following error: type == kMetaAssetType && pathName.find ("library/metadata") != 0. Reading online is states this is likely due to trying to open an newer project in an old version of unity.

I had been assured that the project I am working with is version 3.5.7 so I read online that you can determine the unity version the scene was created in (I guess last saved in would be more accurate?) by opening the scene in a text editor and the version should be in the first line. The three scenes are stating the following versions.

3.5.0f5 3.4.1f5 4.3.4f1

I have tried opening the 3.5.0f5 scene in unity 3.5.0, 3.5.5 and 3.5.7 all with no luck. I also completely uninstalled unity (including preferences, logs, angry bots and licence file) and reinstalled 3.5.7f6 and reentered the pro licence and tried to load the 3.5.0f5 scene and got the exact same error, so maybe its related to the file itself and maybe the different versioning of the scenes.

So my question is: In a unity project (in my case 3.xx) with three scenes, if any of the scenes are opened in a later version (say 4.xx) and saved how does this affect the project overall? Is it a 3.xx project or a 4.xx project?

Thanks

Answer 1

It will turn into a higher version. We have Unity 5 now. So I suggest you update. If your scene is using Nav Mesh. You will have to re bake your Nav mesh as it will removed when upgrading. Manual For those who have a manual Nav Mesh scenes, this is a nightmare transition. Other than that. YOU SHOULD Update your Unity to the latest, Not having the new UI of Unity is a big draw back for you. Trust me.