Hello @rgelb,
Very sorry you're having troubles with the upgrade required in this case.
I am saying fix v6.6 of the ODBC driver that people paid for.
Supporting LinkedServer however required changes that applied both to the driver and the server and that are considered features, such as the artificial varchar limitation required by LinkedServer or adapting to its incapacity to work with BASE TABLEs.
No recent product Microsoft has rolled out requires these workarounds, LinkedServers is however not based on new code. I'd happily open a support request with Microsoft around these issues, but I think I know how it would end up.
In any case, we're happy to meet our users where they are and doing efforts to accommodate their applications. And we are making fixing backports back into the supported versions.