Are you talking about https://en.m.wikipedia.org/wiki/Common_external_power_supply? This wasn't a mandate, it was just a recommendation.

No it was never mandatory only voluntary. There was a threat to make it mandatory but most mobile phone suppliers signed a letter of intent on implementing a common standard (apple included).

This is incorrect. It was a voluntary standard signed on by a non-binding MoU. All Manufacturers were free to "break" the agreement when moving to USB-C. Now they are stuck on USB-C until a new law is written.