Apple's beta releases continue to yield clues about unannounced hardware, with Tuesday's macOS Big Sur 11.3 beta including references of two new iMac designations.
According to the site, "iMac21,1" and "iMac21,2" correspond to iMacs codenamed J456 and J457. In January, Bloomberg outed those designations as next-generation replacements for the current 21.5-inch iMac and 27-inch iMac, which are due for a refresh this spring.
Apple is widely expected to soon unveil a new iMac line powered by a variation of its M1 chip. Previous reports point to a redesigned chassis that borrows features from Apple's angular iPhone and iPad devices. New color options are also rumored.