In 1.3.3 the protected createRestrictor() call was removed. The only avenue now for creating a custom restrictor is via the constructor. This is problematic as we override init() to perform configuration, and that happens after construction. The instance variable is private and there is no setter, so there's no way to replace the restrictor after construction.

Either the protected createRestrictor() needs to come back, or the instance variable needs to be made protected rather than private or a protected setter added to allow subclasses to replace the restrictor between construction and the call to super.init() (or perhaps even at other times).