If you select Automatic for "Update approval" on the "Install Operator" screen under "3.1.2 Deploying Operator", the operator will be automatically upgraded when a new version is published.
If Manual is selected for "Update approval", perform the following steps to upgrade manually.
Select the installed "Fujitsu Enterprise Postgres Operator" from [Operators] - [Installed Operators].
Follow the on-screen instructions to upgrade your operator from [Subscription details] in the [Subscription] tab