Support different behaviors under different versions

If an existing class would greatly benefit from a behavioral change, it would be nice to if the class could, for example, query what version it was instantiated under, and act differently according to the version.

if (runtimeMajor == 1 and runtimeMinor == 0) {
    doSomething(); //old behavior
} else {
    doSomethingElse(); //new behavior
}