An administrator updated the alert and symptom definitions.

Select the checkbox 'Preserve Custom Content' when performing the upgrade: During the upgrade process, you can select the "Preserve Custom Content" option to ensure that any custom content, including alerts and symptoms, is retained during the upgrade to the latest version of vRealize Operations.

Backup the customized content by cloning it: Before upgrading, it's a good practice to backup customized content by cloning it. This ensures that you have a copy of the custom configurations in case they are lost or need to be restored after the upgrade.