A lot more information is needed. Start with the basics:
1. Are you using TurboActivate or TurboFloat?
2. What version of TurboActivate or TurboFloat are you using? If it's not the latest, do that before doing anything else. There's absolutely no reason you should waste your time or we should waste our time tracking down bugs that have already been fixed. It sounds like you're using an old version (from the problem the customer is describing)
3. What operating system is the customer running on?
>> "Another problem is that the License manager is not backward compatible."
The TurboFloat Server? Yes, it is. Use the latest version and it supports all old versions of the TurboFloat Library.
TurboActivate? Yes, it is as well. It fully supports all old activations and upgrades them to the latest format.
TurboActivate is not *forwards* compatible (meaning old versions of TA cannot understand *new* formats). But that's a given. We cannot go back in time and program our old versions to learn how to read the new formats.
>> "Still, the question remains why it doesnt work if Wireless Network connection is disabled?"
It doesn't on modern Windows. On modern Windows (8, 8.1, and 10) you can disable all network adapters and everything will just work. On ancient Windows (7, Vista, XP) network adapters must be enabled *briefly* so TurboActivate can accurately "fingerprint" the computer.
Again, this is covered in our FAQ because it's a frequently asked question: https://wyday.com/limelm/help/faq/#disabled-adapters