Solved! Go to Solution.
You DO need a working license for an enterprise (ArcSDE) geodatabase. Connections
will not work if the license is invalid, but this isn't just application server connections,
it's ALL connections.
A working license ISN'T required to install an application server, but it IS required to
start the service.
ArcGIS 10.1 and 10.2 share the same license files, but if your old geodatabase was
pre-10.1, then you'd need to authorize a new license in the geodatabase.