Your question is literally answered in the article:
> Even without finding the plane, a number of lessons have been drawn from the disappearance of MH370. Many of the responses to the disappearance centered on the fact that in the 21st century, commercial airliners should not just disappear. In the interest of knowing where every plane is at all times, the International Civil Aviation Organization (ICAO) began requiring that all airliners manufactured after the 1st of January 2021 include autonomous tracking devices that broadcast their location once per minute. To give greater coverage of airplanes manufactured before that date, Inmarsat (which supplies satellite relays to nearly all commercial airliners) changed the frequency of its handshakes from once per hour to once every 15 minutes. The European Aviation Safety Agency began requiring that the “pingers” on aircraft flight recorders last at least 90 days, rather than 30. ICAO also amended its guidelines to require that airliner designs approved after 2020 include cockpit voice recorders that record 25 hours of conversations (instead of the current standard of two), and that flight data recorders either stream data to a location on the ground or be designed to float to the surface after a crash. (Like all ICAO regulations, these only come into force if adopted by the member states, which may take some time.)
I think now, after another documented murder-suicide, there's also been a change in regulations requiring at least 2 people to be in the cockpit at all times. Other commenters point to additional changes