1# Ability Subsystem Changelog 2 3## cl.ability.1 Added the Verification to Check Whether the Caller to Start a UIExtensionAbility Is Running in the Foreground 4 5**Access Level** 6 7Public API 8 9**Reason for Change** 10 11The UIExtensionAbility can be started only by an application running in the foreground. However, the system does not check whether the caller is a foreground application when the application attempts to start a UIExtensionAbility. 12 13**Change Impact** 14 15This change is a non-compatible change. 16 17Before change: A background application can successfully start a UIExtensionAbility. 18 19After change: A background application fails to start a UIExtensionAbility. 20 21**Start API Level** 22 2311 24 25**Change Since** 26 27OpenHarmony SDK 5.0.0.39 28 29**Key API/Component Changes** 30 311. **UIAbilityContext.startAbilityByType** and **UIExtensionContentSession.startAbilityByType** 32 332. APIs that have the capability to start a UIExtensionAbility 34 35**Adaptation Guide** 36 37No adaptation is required. After the change, background applications are not allowed to start a UIExtensionAbility. 38