Apple is now warning Mac users that are using 32-bit apps.
"While developers optimize their apps for 64-bit compatibility, Apple is notifying customers when they are using an app based on 32-bit technology".
Companies are actively trying to push developers and users towards 64-bit apps as this has more or less become the standard now for both mobile and computing devices.
Launching a 32-bit app will obviously trigger Apple's warning, but there's a much easier way to get a full list of all the 32-bit apps you have. It's part of an overall move to remove 32-bit application support from the operating system at some undetermined point in the future.
Instead of just opening all the apps on your Mac, you can easily find out if an app is 32-bit with the following steps. It's also worth noting that 32-bit apps will continue to work in at least the next macOS version the company will unveil this year, macOS 10.14. Developers might still have a few months to work on their apps and transition into 64-bit, if they haven't already.
Starting today, April 12 macOS users will receive notifications carrying info that 32-bit apps will not be supported the operating system's future version. From the system report, scroll down to Software, then select Applications. It first stopped accepting new apps to the App Store that were not 64-bit, and then later stopped launching them. One of the items is 64-bit (Intel). Presently, the App Store does not accept submissions of 32-bit apps for macOS. They can also potentially handle processor requests more efficiently than their 32-bit counterparts.
Apple iOS users who still have 32-bit apps, get a pop-up when they tap that app's icon.
The warnings first appeared on some beta versions of macOS 10.13.4, but as of midnight last night, the alerts should be live for all users running the current software.