Currently, if you wish to sideload an app that's not available on the Google Play Store on a Wear OS device, you can head over to the Apps on your phone section of the on-watch Play Store and install apps that are already available on your phone. However, starting from March 10, 2021, Google is getting rid of this functionality. This will limit users to developer tools like the Android Debug Bridge (ADB) to sideload apps on their smartwatch, making the process much more complicated.

According to a recent post from developer and Reddit user malbry (via Android Police), Google has started sending out emails to app developers alerting them of this change. The email states:

"Starting from Mar 10, Wear OS apps using the legacy embedded app model will no longer show up in the "Apps on your phone" section and will effectively be undiscoverable inside the on-watch Play Store. We encourage developers to migrate to the newer multi-APK model to make their app discoverable on the watches, and to reduce the size of their phone APKs."

For the unaware, the legacy embedded app model allows developers to add Wear OS code to Android apps. This, in effect, lets users sideload apps on their Wear OS devices from the Apps on your phone section. However, Google intends to get rid of this distribution model to make phone apps smaller for everyone. While this move will benefit users who don't have a Wear OS smartwatch, it will make sideloading apps using the aforementioned method impossible. Users will then have to rely on developer tools to push such apps to their Wear OS watches via ADB.

As Android Police explains, the main idea behind this move is to decouple Wear OS apps from Android apps, and it shouldn't affect many users as most developers who publish their apps on the Play Store have already switched over to the new app distribution model. It will predominantly affect apps that aren't distributed via the Play Store, however.