Is my assumption correct?
Thx

Noone has access to Z strategy source code, even if you had the paid Zorro S version. They try to justify it by saying that someone could abuse that knowledge by making trades against the system and making it unprofitable. But I think you raise a good point:
If people were allowed to tinker with these strategies, no two Z-strategy systems would be completely the same, making it impossible for an opposing party to act against it.

I think I didn't explain my question properly. what I meant is that I can't seem to be able to use the Z10 on the free Zorro version, so my assumption is that I can't use Z10, unless I'm on Zorro S, right?
See the screenshot below

I see, yes, guess that's right.

As a rule of thumb, I personally would say there are certain benefits to owning a Zorro S license, but the Z strategies are not one of them. In general, Z strategies suck.

thanks Hredot. It's a very interesting turn for me. Strategies were the only thing I thought were an interesting and differentiating point between Zorro and dozens of other systems.
What did you find to be the most important aspects of Zorro for you?

I like that Zorro is relatively fast for backtests, has minimalist interface while almost unrestricted functionality through coding. If backtests are all you want to use Zorro for, you probably don't need a Zorro S license. However, if you actually want to use it to connect to brokers and perform trades, then the free Zorro version is only a demo version (capital restricted to below $7000, and you can only connect to for example IB broker if you have Zorro S).