The customer that has a support contract. May we send him an IOS with a different feature set, or should he buy the version with the different feature set?
It is good that the customer has a support contract. But the support contract does not provide the authority to change the feature set. The customer bought the router (or switch) with a certain feature set. To change the feature set legally the customer should purchase a license for the new feature set. In general a feature set upgrade license is much less expensive that just purchasing a version of the software.