I just installed the version 28 upgrade.
I had ALREADY purchased the 28-license earlier in the year, and it was installed and operating version-27.
When I installed the 28 upgrade, it DID NOT detect that a valid version-28 license was already installed.
It walked me through the same steps as a regular installation. (I had to go find my license, which of course can't easily be found.)
You ask us to provide you with early funding by letting us buy the licenses months before the software becomes available.
The system should recognize that the update-license IS ALREADY installed, and just install the update when it becomes available.