问题:

Now that Visual Studio 2015 RC is out, has anyone installed it and opened Visual Studio 2013 projects/solutions?

Does it ask the files to be changed?
If yes, are the changes it makes backward compatible?

回答1:

Take a look at the Porting, Migrating, and Upgrading Visual Studio Projects article for Visual Studio 2015. All of the various caveats are described there.

回答2:

Not all types of project are supported. I tried the following 4 project types:

Vb.net Class project, OK.
Vb.net Web Services project, OK.
Cordova JS project, not OK, need to migrate manually, by moving the sources from root directory to the www directory and install all API again.
C#.net winform project, OK.

回答3:

Yes, though you sometimes will have to change the version (single number) in .sln file, no other differences found yet.

We resolved this by typically excluding this file from check in and only check it in when there really was a change (added project, ...) - and then to fix the version before checking in. (Different developer machines with different versions of VS.)

See question Visual Studio 2015 solutions backwards compatibility with Visual Studio 2013 and answer https://stackoverflow.com/a/31540590/586754.

(Assuming you are having basic projects that are supported by both versions, like C# and .net framework that is supported by lower version VS.)