Hi Habibgha, Are you hoping to carry out an inplace upgrade of the OS? This should work but I'm not sure if it has been tested. Assuming your infrastructure servers are virtualized, perhaps you could take  snapshot or clone this Virtual machine and attempt in a lab environment? Or you could work on a phased approach, the first step being, if your current farm is 8.0.1 you could upgrade all the roles on your current server on 2008 R2 to vWorkspace 8.5, then build a separate new VM with 2012 R2 and install IIS and the vWorkpace Web Access role. Create a new vWorkspace web access site on the new server just for the HTML5 connector.  I hope that helps! Thanks, Sam
Dears, I would like to know if there is any risks upgrading the OS of the server holding the connection broker, profile management and web access from windows server 2008 R2 to windows server 2012 or higher to enable support for HTML5 connector? please advise what is the suitable scenario for such upgrade. Regards 
Upgrade connection broker to windows server 2012