The evolution of car designs to improve fuel economy and reduce exhaust emissions has led to vehicles more powerful and less polluting but also with increasing temperatures under bonnet.
Nowadays most OEMs require a DOT 3 brake fluid or DOT 4 brake fluid level to assume this range of temperatures and constraints.
At the moment standard organizations aren’t working on a new specification.
Nevertheless each OEM is launching or has already launched its own specifications based on DOT 3 brake fluid or DOT 4 brake fluid officials with additional tests and severe limits. It’s a kind of DOT 4 brake fluid + or Super DOT 4 specification.