Detect file format version and refuse to open incompatible files

Scenario:
1. Ralph sends a file that he created in the latest version of MuseScore to his friend Sally.
2. Sally opens the file in an older version of MuseScore, makes changes and sends the file back to Ralph.
3. Ralph replaces his original file with the one Sally sent him.
4. Later Ralph opens the file Sally sent him and notices it is corrupted

Discussion:

Often people notice glaring problems in step 2 (such as opening a 0.9.6 file in 0.9.5), but since they are not aware of the reason for the odd looking score they continue to save the file. In the past few months, more than one forum user has done this.

The issue becomes especially critical when a person has two versions of MuseScore installed and the person makes edits to the same file using different versions of MuseScore.

Recommendations:

Probably the safest option is for MuseScore to refuse to open a file with an incompatible file version number . Accompanied with a message that explains why the file won't open and what the user can do to open it.

I don't know enough about the file format numbering to know whether every iteration represents a breaking change or whether it would be worthwhile to add a compatibility tag to each file that says that it is compatible with file format version X.XX or higher.