Apple App Store

• App Store will help users understand an app’s privacy practices before they download the app on any Apple platform. App developers can now enter their app’s privacy information in App Store Connect. This information will be required to submit new apps and app updates to the App Store starting December 8, 2020. Existing apps will remain available for download.
  Full content and details (external sources): Developer.Apple
  

• iPhone and iPad apps will be available to the Mac App Store on Apple silicon Macs.
  Full content and details (external sources): Developer.Apple

• Developers can now create subscription offer codes to acquire, retain, and win back subscribers.
  Full content and details (external sources): Developer.Apple
  

• Deadline extended to June 30, 2021 for online group event in-app purchase requirement.
  Full content and details (external sources): Developer.Apple
• New apps and app updates will not be accepted December 23 through 27 (Pacific Time).
  Full content and details (external sources): Developer.Apple

• Source App ID and Conversion Value now available in SKAdNetwork 2.0
  Full content and details (external sources): Developer.Apple

• You can now submit apps built with Xcode 12.3 beta using the SDK for iOS 14.3 beta, tvOS 14.3 beta, and watchOS 7.2 beta for internal and external testing.
  Full content and details (external sources): Developer.Apple

Google Play Store

• If your app uses background location data, you must submit a form for review and receive approval by January 18, 2021 so your apps can stay on Google Play. Existing apps first published before April 16, 2020 have until March 29, 2021 to comply.
  Full content and details (external sources): Android Developers Blog

• New Android App Bundle and target API level requirements in 2021
  Full content and details (external sources): Android Developers Blog

• android-kotlin-extensions will be removed in a future Kotlin release during or after September 2021
  Full content and details (external sources): Android Developers Blog

Huawei App Gallery

• With AppGallery, Huawei Facilitates Access to Chinese Market for Global Developers.
  Full content and details (external sources): PRNewsWire