PROB § 601

If the law existing at the time of the creation of a power of appointment and the law existing at the time of the release or exercise of the power of appointment or at the time of the assertion of a right given by this part differ, the law existing at the time of the release, exercise, or assertion of a right controls. Nothing in this section makes invalid a power of appointment created before July 1, 1970, that was valid under the law in existence at the time it was created.