Is there an in place upgrade from XenDesktop 5.5 to version 5.6 you ask? Well yes Virginia, there is. In fact, I recently did it. There really is nothing to it.
You will need to upgrade your license server to at least version 11.10. (Supported Platforms: Windows 7 (32/64bit), Windows Server 2008R2, Windows Server 2008 (32/64bit), and Windows Server 2003 (32/64bit). This shouldn’t present a problem for anyone but check and back up your system and licenses before upgrading.
Download the upgrade from Citrix’s web site. Of course a login is required. As you may know, the full download of XD is a hefty 20.6 GB. This includes everything. You can do a custom download and only select the pieces you need.
The installation was literally a wizard with a couple of clicks and Finish. When you start Desktop Studio for the first time after the upgrade, there will be an option in the center console to upgrade the database. Both an automatic and manual option are available. If you select Manual, it gives you the Powershell commands to upgrade the database yourself if you are so inclined or have a need to do so. I selected Automatic.
That was about it. Happy upgrading.