Apples developer site this past Friday has shared that starting on January 1st of 2018, 32-bit Mac apps would no longer be accepted into the store.We saw that earlier this year that iOS 11 no longer is compatible with 32-bit apps therefore Apple no longer accepts them on the iOS App Store either, the same thing is now coming for the infamous Mac App Store.
Apple stated that all new apps submitted to the Mac App Store must support 64-bit architecture staring January 1st. Existing 32-bit apps must be updated to 64-bit by June 2018.
Official statement from Apple:
As a reminder, new apps submitted to the Mac App Store must support 64-bit starting January 2018, and Mac app updates and existing apps must support 64-bit starting June 2018. If you distribute your apps outside the Mac App Store, we highly recommend distributing 64-bit binaries to make sure your users can continue to run your apps on future versions of macOS. The last macOS release to support 32-bit apps without compromise is macOS High Sierra.