The writing’s been on the wall, more or less, since all the way back in 2009 when Apple began its 64-bit transition with the release of Snow Leopard. Last year, Apple warned Mac developers that 32-bit apps would stop running “without compromise” this fall with the release of the successor to macOS High Sierra. The warning was news, but this is actually a story long in the making. It was minor news last week: In another step along the transition to 64-bit apps, Apple began warning users of 32-bit apps that these apps would need to be updated or they will stop running.
