Without further information, it is not possible to determine which driver had an issue with the upgrade. Are you able to place the connector into debug logging, reproduce the issue, collect the log and file a case with TAC to investigate?
I had totally same issue as you have described. And I worked it with TAC engineer.
I would say that there was upgrade to 7.1.5 with "skipdfc 1" switch which caused the 6.x NetworkDriver (DFC) to be left there, without upgrade. Due to this you cant upgrade from 7.1.5 to 7.2.7. In order to have correct dfc driver installed. You have to do clean install. Uninstall 7.1.5/reboot/install/7.2.11. --> this is the only possible clean solution for this issue at the moment. . I already asked for a hotfix via TAC case.
To workaround the problem currently, you can go ahead and upgrade using switch "/overrideupgradefailure 1 ", but this leave old dfc driver intact and next upgrade will say the same error message.