New configuration to allow updates to cases in resolved and canceled status
Previously the resolved or canceled case records on Dynamics 365 and Dataverse tables couldnt be updated. You can’t update a read-only record from the UI anyways but even if you try to do it via a workflow, a plugin or api, you would get the following error:
Since case is resolved and read-only, only these attributes are updatable : “ownerid”, “owneridyominame”, “owneridtype”, “owninguser”, “statecode”, “statuscode”, “modifiedon”, “modifiedby”, “modifiedonbehalfby”, “owningbusinessunit” , “processid”. If you need to edit other fields, please reactivate the case
Thus you should be activating the case, making the update and deactivate it again. This is changing with the new feature update in the 2021 Wave 1 release.
After the release you will be able to update read-only case records without activating them via a Power Automate flow, an API or a Plug-in run by an admin user. For the end-users the records will still be read-only. And you wont be able to update the record with a legacy workflow.
here is the related microsoft doc page: https://docs.microsoft.com/tr-tr/dynamics365-release-plan/2021wave1/service/dynamics365-customer-service/configuration-allow-updates-cases-resolved-canceled-status