The FailOverToOldVerifier option affects whether or not class file version 50 class files can get verified by the inference verifier if they failed verification with the split verifier.

The default value for FailOverToOldVerifier is TRUE, meaning that class file version 50 class files can failover to the inference verifier.

It is doubtful that anyone runs with FailOverToOldVerifier set to FALSE. So the option should be deprecated, always allowing class file version 50 class files to failover.

The option was initially added to help byte code emitters test adding support for stack maps in class files.