On December 28, 2020, the FAA released new final rules for certain uses of Unmanned Aerial Systems, (UAS, or drones), the result of a multi-year undertaking.  These new rules build upon previous rulemakings which expanded UAS operations to allow for commercial use and eased restrictions for those operators, along with creating the small-UAS (less than 55 lbs) and micro-UAS (4.4. lbs or less) categories of vehicles.  The new regulations do several things: 1) they require remote identification technology for UAS; 2) they expand UAS commercial operations to allow for over-crowd flights, creating different restrictions based on the category the UAS falls into (more below); and 3) they establish a system for allowing operators to conduct UAS flights at night.  
Previously, the FAA had allowed commercial UAS flights only over people on the ground who were participants in the operation itself.  Under the new regime, certain types of UAS will be able to fly over crowds regardless of their knowledge or participation in the operations; others will have more restricted abilities.  To accomplish this, the FAA created new categories for UAS.