All new apps submitted to the Mac App Store must have 64-bit support, and all app updates and existing apps must support this by 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,” Apple wrote in a statement. To ensure that the apps you purchase are as advanced as the Mac you run them on, all future Mac software will eventually be required to be 64-bit.”