Hello Ulf,
Sorry, but I´m right (because I´m one of the programmers).
The point is, that when Win-Digipet 8 has been published (around 2001/2002) Lenz only offered the LI-100 and LI-101f, but no one talked about the LI-USB.
When they publised the LI-USB they changed the interface code compared to the one of the LI-100 and LI-101f, so the interface structure in WDP had to been changed to adapt WDP to the new functionality and this has been done for Version 9.1.
And the additional functionally of version 3.6 had been published in the times of WDP ProX and then we added these functionality also for all following updates and versions of WDP. But 3.6 will also work with the former versions, but only with the 3.6 functionality.
If you take a look in the manual of your version 8.x the only mentoined interface are the Li100 and Li101f, but there is no word about the LI-USB. And the manual is also only talking about Lenz 3.0. There is the latest update of version 8 even better than the manual, because there Lenz 3.5 has been included.
So there is no cheating by Win-Digipet. It is normal, that there are some free updates for a software (8.1 to 8.4) and after quite while further function enhancement has to been paid (upgrade).
Regards
Markus
