s4:OnLaunch

Article
05/07/2024

Description

Specifies whether the deployment service will check for an update to the App Installer file on the app launch. (s4:OnLaunch)

Element Hierarchy

s4:AppInstaller

s4:UpdateSettings;

<s4:OnLaunch>

Syntax

<s4:OnLaunch     ShowPrompt? = Boolean.
    UpdateBlocksActivation? = Boolean.
    HoursBetweenUpdateChecks? = Unsigned byte.
></s4:OnLaunch>

Key

? optional (zero or one)

Attributes

Attribute	Description	Data type	Required
ShowPrompt	Indicates if deployment will show a prompt, informing the user about the update. For more information about the behavior of this attribute, see the remarks. Available in Windows 10, version 1903 and later.	Boolean.	No
UpdateBlocksActivation	Should only be used if ShowPrompt="true". Indicates if deployment will stop the user from launching the application until the update has been applied. “UpdateBlocksActivation” = true means the UI the user will see allows the user to take the update or close the app. “UpdateBlocksActivation” = false means the UI the user will see allows the user to take the update or start the app without updating. In the latter case, the update will be applied silently at an opportune time. For more information about the behavior of this attribute, see the remarks. Available in Windows 10, version 1903 and later.	Boolean.	No
HoursBetweenUpdateChecks	Specifies the frequency with which the the deployment service will check for an update to the App Installer file. When HoursBetweenUpdateChecks is set to 0, the deployment service will check for updates every time the application is launched. For other values, the deployment service will check for updates when the application is launched only if it hasn't previously checked within the last number of hours specified by HoursBetweenUpdateChecks. For example, if HoursBetweenUpdateChecks is set to 12, the deployments service will check for updates when the application is launched only if it hasn't already checked for updates in the previous 12 hours.	Numeric values between 0 and 255 inclusive. The default is 24.	No

Parent Elements

Parent Elements	Description
s4:UpdateSettings	Specifies settings related to app updates.

Remarks

Setting the ShowPrompt="true" attribute currently shows a prompt for UWP applications but not for desktop applications that have been packaged in a Windows app package (that is, desktop applications that use the Desktop Bridge). For desktop applications, this functionality provides a silent update; the same default functionality provided by the OnLaunch element.

The ShowPrompt and UpdateBlocksActivation attributes have effect only when the user starts the app from a menu item or tile in the Start menu. These attributes have no effect if the user starts the app from a desktop shortcut or from the Taskbar.

Examples

In this example, deployment will check for updates every time the app is launched. If updates are found, deployment will show a prompt telling the user they must take the update before launching the app. Also the app version can be incremented or decremented.

<s4:UpdateSettings> 
    <s4OnLaunch s4:HoursBetweenUpdateChecks="0" s4:ShowPrompt="true" s4:UpdateBlocksActivation="true"/>
    <s4:ForceUpdateFromAnyVersion>true</s4:ForceUpdateFromAnyVersion>
</s4UpdateSettings>

Requirements

Requirement	Value
`xmlns:s4=http://schemas.microsoft.com/appx/appinstaller/2021`	This namespace is required for features introduced in Windows version 21H2 build 22000
Minimum OS version	Windows version 21H2 build 22000

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