1# ArkUI Subsystem Changelog
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3## cl.arkui.1 uiAppearance API Behavior Change
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5Changed the return mode and return value of the **setDarkMode** and **getDarkMode** APIs.
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7**Change Impact**
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9The application developed based on earlier versions needs to adapt to new return mode and return value. Otherwise, the original service logic will be affected.
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11**Key API/Component Changes**
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14- In the error thrown when the **setDarkMode** API is called in callback mode, what's contained changes from error code ID only to error code ID and message.
15- In the error thrown when the **setDarkMode** API is called in promise mode, what's contained changes from error code ID only to error code ID and message.
16- In the value returned in normal cases when the **setDarkMode** API is called in callback mode, the first parameter changes from **0** to **null**.
17- In the earlier version, the **getDarkMode** API directly returns **2** when an exception occurs. In this version, the API throws an error. You need to determine the error type based on the error code ID and message.
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19> **NOTE**
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21> Exceptions refer to unexpected behavior such as incorrect parameters, unconfigured permissions, and internal execution errors. Normal cases refer to expected behavior that do not generate errors.
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23**Adaptation Guide**
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25For details, see [@ohos.uiAppearance (UI Appearance)](../../../application-dev/reference/apis/js-apis-uiappearance.md).
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