Processors, operating systems, and programs can all be 32-bit or 64-bit. While 32-bit was once the standard, 64-bit has taken over as technology has progressed. macOS has been exclusively 64-bit since Mac OS X Lion released in 2011, but Macs are still compatible with older 32-bit software. However, that’s set to change soon. 32-Bit App Support on Mac Will End Some Mac users have started seeing a vague warning when launching 32-bit apps that the apps “need to be updated by [the] developer to improve compatibility”.