Refer to the specific documentation related to the released version of XenDesktop that you are using for any release-specific detail. Specific documentation can be found on Citrix eDocs. When upgrading an existing XenDesktop 5 site to a new release or applying a hotfix, the following best practice procedure is strongly recommended:
Back up your Site
Back up the database for the site. This should be performed regularly in any case, but a backup just prior to any major change is advisable. Ensure that the backup completed successfully without any reported errors.
Upgrade the License Server
If you upgrade the license server during the XenDesktop upgrade, ensure that the license server is upgraded before any of the other XenDesktop controllers. If the license server is installed on a separate server, update this server before any of the other servers. If licenses have been purchased through the Subscription Advantage program, ensure that the license has been renewed recently enough so that the license issue date is within one year of the release date of the version of XenDesktop you are upgrading to.
Upgrade half of your Desktop Delivery Controller Servers
Choose half of your servers to upgrade or apply the hotfix to first, leaving the other half of the servers to keep the site running during the upgrade activities. On the first half of the servers, apply the upgrade or hotfix installers and restart the server. The upgraded servers might now be incompatible with the earlier form of the database, so they might not participate in the functioning of the site at this point; this is expected and the site can keep functioning using the non-upgraded servers until the database is itself upgraded.
Upgrade the Database
Using the most recent version of Desktop Studio (that is: if upgrading to a new release that includes a new Desktop Studio version, the upgraded Desktop Studio should be used), start Desktop Studio and view the dashboard for your site. There is an Update button at the top of the dashboard which allows you to perform the update. When performing the update, you are given the option of either having Desktop Studio apply the update directly to the database, or having Desktop Studio provide you with scripts which you can run on the database at another time. If you wish to have Desktop Studio apply the update directly, you must run Desktop Studio as a user with the db_owner role on the database.
When applying the upgrades directly from the Desktop Studio, a progress dialog is displayed followed by a success message. The success message notifies you if there are any controllers you need to upgrade having completed the schema upgrade.
When you get the scripts from the Desktop Studio, then a directory window appears containing the script or scripts you need to run. Further instructions on the use of these scripts are detailed in the header at the top of each script.
The upgrade to the database might require the site to be off-line while the actual database changes are performed. This is managed for you by Desktop Studio if it is applying the upgrade directly, but if the upgrade database script is to be applied manually, all the controllers in the site must be stopped while the script runs.
The database might now be incompatible with the non-upgraded servers, so they might not participate in the functioning of the site at this point, but the database should now be compatible with the servers that were upgraded earlier, which should allow the site to continue to function while the remaining servers are upgraded.
Upgrade the remaining Controller Servers
For any of the servers not chosen to be upgraded in the earlier upgrade step, apply the upgrade or hotfix installers and restart the server. All the servers should now be upgraded and the site should now be functioning at the fully upgraded state.