We're trying to apply SP1 to SharePoint 2013 on a Clients farm. We've sucessfully done this on their test environment and are pretty happy with the steps to take.
However, on one of the Application Servers in the Production Farm the status of the Server is 'Upgrade Blocked' and the rest say 'Installation Required'
I've googled Upgrade Blocked but the only articles I can find are not very helpful. Hence my queston here.
Is this because this server needs patching to same level as the other servers in the farm ? Or is this server patched to a higher level than all the others and will be excluded from SP1 being applied ? Or is it something else entirely ?
Thanks in advance for all advice/information