In an internal memo distributed to Apple Authorized Service Providers, Apple has indicated that the Late 2012 model 21.5-inch and 27-inch iMacs will be added to its vintage and obsolete products list on January 30. 

Vintage and obsolete products are typically no longer eligible for repairs or replacement parts from Apple or Apple Authorized Service Providers, but the memo states Late 2012 model iMacs will be eligible for Apple's pilot program that will permit extended service through January 30, 2021, worldwide, subject to parts availability. 

Other products in the pilot program include the iPhone 4S, iPhone 5, Mid 2012 models of the MacBook Air and Mac Pro, and Mid 2012 to Early 2013 models of the MacBook Pro. The program began in January 2018 and was expanded in August. 

Vintage products are those that have not been manufactured for more than five years, according to Apple.

Source: macrumors