One of the hallmark features of Android is the ability to allow users to install apps even outside of the Play Store. This is called sideloading and it is useful if you need to test apps or if you’re creating apps for a specific use and don’t want to go through the hassle of submitting it for review.
That being said, there is potential for abuse which is why according to recently updated guidelines for the Google Play Store, it seems that Google will be blocking the sideloading of apps that target outdated versions of Android.
“When you upload an APK, it must meet Google Play’s target API level requirements.
New apps must target Android 12 (API level 31) or higher; except for Wear OS apps, which must target Android 11 (API level 30) or higher.
Starting in January 2023, app updates must target Android 12 or higher and adjust for behavioral changes in Android 12; except for Wear OS apps, which must target Android 11 or higher.”
The reason for this is simple: sometimes there are exploits and vulnerabilities found in older software builds, which is why it is generally recommended that users keep their apps and devices updated. Hackers might try to capitalize on this by creating apps that try to exploit these vulnerabilities in older versions of Android, so blocking the sideloading of such apps could potentially cut back on these types of problems.
Of course, this won’t completely stop malware from being spread or installed, but it could make it a bit harder.