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Updating the manifest file
When After updating the manifest .xml file (NOTE: this does not apply to the case where not after updating the website itself has been updated) make sure to increment to ID-field of the manifest file. If a user doesn't ), a user might not see the effects of the changesupdate immediately. To fix this, try following the steps under "Remove an add-in from local cache" aton the user's computer: https://docs.microsoft.com/en-us/office365/enterprise/use-the-centralized-deployment-powershell-cmdlets-to-manage-add-ins?redirectSourcePath=%252farticle%252f94f4e86d-b8e5-42dd-b558-e6092f830ec9#delete-an-add-in
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