(Undocumented) Issues when Upgrading to XenDesktop / XenApp 7.6
During the last days I tested the Upgrade from XenDesktop 7.5 to XenDesktop 7.6. I found some interesting “Issues” during the upgrade which seem to be not documented.
Upgrading StoreFront on a separate System
If you upgrade StoreFront on a separate Server and use the Upgrade Wizard you receive the following message: 
As you can see the Upgrade process try’s to check something which is not available on a standalone StoreFront system. Luckily you can ignore the warning and continue with your installation. Actually StoreFront even doesn’t check the licenses later – so even if no licenses are available StoreFront works.
Upgrading Citrix License Server on a separate System
The more confusing message is shown if you use the Upgrade Wizard to upgrade the Citrix License Server which is not installed on a Delivery Controller. If you try to upgrade the following message is displayed:
This product requires a newer license. You must install a license with a Subscription Advantage date of “2014.0815” or later.
Even if you have licenses with a Subscription Advantage date after “2014.0815” the message is displayed. Luckily you can also safely ignore this message (of course only if your Subscription Advantage date is after 2014.0815) – your users will still be able to access their Desktops and Applications.
Jan Hendriks Blog 
I had the same error last Sunday when upgrading from 5.6 to 7.5. I did check the box and continue but when starting the Desktop Studio it does need a valid License Server and License File to upgrade.
Now I have a partially upgraded environment which is not stable. I do not suggest to continue when these errors show up.
I did not continue and logged a case at Citrix. They did not find a solution and I now created a new XD 7.5 environment, pointed to the same License Server and File and guess what, they are valid.
Ok – that’s strange – I only upgraded from 7.5 to 7.6. Did you try to redownload the license files? Remove all old ones and only add the new one?
I did, but the new installation works fine with the same license server and file. So these are ok.
It must be something in the wizard.
Hm – sounds like a Problem in the upgrade wizard – do Connections also fail or does only Studio Display the error message? Did you try to upgrade to 7.6?
I did a rollback (vm snapshot) to 5.6 but because I continued the installation (the checkbox) it did modify something in the database. When I start XD 5.6 studio it says there is a database upgrade. Customer does not want to upgrade to 7.6. I build a new environment and going to migrate to a clean greenfeeld environment. Feels much better then an upgrade.
It already modified something in the Database? Ok – I always thought that’s first Happening after starting Studio and saying: Upgrade Database.
Green Enviroment is always a good Point to clean up some old mess 🙂
I think it did not modify it but there were some changes in the DB (maybe an upgrade flag or something) because now it says in 5.6 studio that there is an upgrade available. And since i did a rollback it must be in SQL and not on the local machine.