On Tuesday we learned overtime would become a 5 minute 3-on-3. Here are the actual mechanics of how it will work with regards to penalties:
If a team ends the 3rd period on a 5-on-4 power play, it will continue in overtime as a 4-on-3 power play. A 5-on-3 power play at the end of regulation will continue in overtime as a 5-on-3.
Taking a penalty during the overtime period will have the same result. The team on the power play will ice an extra skater to create a 4-on-3.
There will not be any situation where a team plays has than 3 skaters on the ice.