The title says it all really.

Modifications to the framework need to be approved by Ken Schwaber and Jeff Sutherland (co-creators of Scrum), and to be honest there are likely to be very few, given it’s such a simple framework.

The more interesting thing to keep an eye on will be the Extensions.  As a Scrum Coach and Trainer, I’m often asked what teams should do in a specific scenarios.  Scrum is silent on those situations because they aren’t generic enough, and yet there are generally accepted, healthy behaviours teams should have in those situations.  That’s the essence of an extension.  The healthy, beneficial practices team can use to complement Scrum to help teams in Situation X.

This a is great move by Scrum.org and a very welcome one!

Scrum Extension Library and Submission Guide

Scrum Modification Submission Guide