In August Apple increased the period in which customers can extend their AppleCare+ coverage after it expires. As noted by MacRumors, the tech giant used to allow coverage to be extended for 30 days after the end of the original AppleCare+ plan, but that has now changed to 45 days.
The AppleCare+ extension support document says you can purchase the new coverage within 45 days after your original coverage ends. To find out if you can purchase the new coverage, go to mysupport.apple.com and follow the onscreen instructions. The new coverage automatically renews until canceled.