Specifically, ARM will be removing 32-bit support from the “big” chips. Mo mention of the “LITTLE” ones, which may mean they get to keep the legacy 32-bit support. For context, the company has this chip architecture called “big.LITTLE”. The former is the more powerful one while the latter are the more efficient ones. For most users, this shouldn’t be a problem. Most devices that use ARM chipsets are Android devices. And the Android mobile operating system itself has been 64-bit since the days of Lollipop.
Most apps are also already 64-bit code, and this will mean app makers will not have to maintain the 32-bit versions. Though in extremely fringe situations, if you’re still using very old apps that still run on 32-bit, they may not be usable anymore on devices using the new hardware. But that will not be the case for a very long time still. After all, ARM said these chips will only be made in 2022, and devices using them will only come after that. (Source: ARM)