When attempting to deploy Spring Cloud Services 3.2.x+, the upgrade all instances error fails with:
The status before upgrade was 'failed' with message 'CF-UnprocessableEntity(10008): Stack must be an existing stack'.
Spring Cloud Services 3.2.x+
Starting in Spring Cloud Services 3.2.0, a field call "Stack property" has been added to the tile configuration. The default value for this field is cflinuxfs4
https://docs.vmware.com/en/Spring-Cloud-Services-for-VMware-Tanzu/3.2/spring-cloud-services/GUID-release-notes.html#v3.2.0
In situations where you are only using cflinuxfs3 buildpacks and not cflinuxfs4, you will hit this error.
To resolve this, please verify what value is present in Spring Cloud Services tile -> SCS Service Broker -> Stack. If the default value of cflinuxfs4 is set, and you are not using that stack for your buildpacks, you will need to change that value instead to cflinuxfs3.
If you are unsure which stack you have available, you can run cf buildpacks and check what stacks are available in your environment.