The Android OS has permitted applications to modify the behavior of other apps using Accessibility Services for a number of years now. The official purpose of this API is to allow developers to create apps for users with disabilities, but it is often utilized in other capacities like filling in text fields and overlaying content. A few applications that currently rely on the Accessibility Services API are Network Monitor, LastPass, Universal Copy, Clipboard Actions, Cerberus, Tasker, and Greenify.

Although Accessibility Services can enhance the overall functionality of applications, they also can pose a security concern because once granted the proper permissions, the API could be used to read data from other apps.

Google has contacted developers regarding the official policy on the usage of this tool, and it's likely due to the previously mentioned security risks.

The developer of BatterSaver received the following email:

We're contacting you because your app, BatterySaver System Shortcut, with package name is requesting the 'android.permission.BIND_ACCESSIBILITY_SERVICE.' Apps requesting accessibility services should only be used to help users with disabilities use Android devices and apps. Your app must comply with our Permissions policy and the Prominent Disclosure requirements of our User Data policy.
Action required: If you aren't already doing so, you must explain to users how your app is using the 'android.permission.BIND_ACCESSIBILITY_SERVICE' to help users with disabilities use Android devices and apps. Apps that fail to meet this requirement within 30 days may be removed from Google Play. Alternatively, you can remove any requests for accessibility services within your app. You can also choose to unpublish your app. [...] Alternatively, you can choose to unpublish the app. All violations are tracked. Serious or repeated violations of any nature will result in the termination of your developer account, and investigation and possible termination of related Google accounts. If you've reviewed the policy and feel we may have been in error, please reach out to our policy support team. One of my colleagues will get back to you within 2 business days.
The Google Play Review Team

Other developers have confirmed they received the same communication from Google and there is also a Reddit thread full of similar reports. Developers will need to do one of the following three actions to comply with Google's policy on the Accessibility Services API.

They will either need to convince Google that users with disabilities will benefit from using their application, downgrade the functionality of the app, or unpublish the application entirely. However, apps like Greenify, rely heavily on the API and can't function without it.

This will affect hundreds of programs currently in the Google Play Store, especially apps intended for power users and customization. Drop a comment below and let us know what you think of the change.

Via AP