Using WebCore with XData

The classes.pas I have is dated 13-02-2018. The directory is made by the installer on 6-6-2018, using version dated 5-6-2018 downloaded and installed from the Subscription Manager v2.0.1.1.
In the subscriptionmanager I see this:
available 5/6/2018
downloaded 30/12/1899
installed 6/6/2018
So it looks like I downloaded the right one, but installed an older one. But I do all these things using the Subscription Manager. The problem must lie in the Subscription Manager then, I guess.
I did not reinstall yet.

Can you try to do an uninstall from the Windows Control Panel of the TMS WEB Core installer for the specific Delphi version you use and then reinstall from TMS Subscription Manager, that should solve the problem.

When I removed only the installed version of Delphi Tokyo that did not help. I found the directory the Web core installer was using and saw that there indeed were versions from February in there.
I then also removed the Webinstaller, but then I could not install from the Subscription Manager anymore and I also could not download again.
Finally I found the Web Core setup in AppData\Local\tmssoftware\TMS WEB Core\ and I installed that and now I have the right version.
The error in XData.Web.Connection does not occur anymore. I now have to eliminate other errors in my own code to get it to work, but that's ok.
Maybe you can give me some general guidance how to proceed.
The pas2js compiler complains about a lot of general units. Some I can replace with their webversion, like system.classes, system.sysutils or system.dateutils. But for others I have no equivalent, like system.Generics.Defaults or system.Generics.Collections.
The pasjs compiler also complains about every Aurelius unit I use.

At this moment, there is not yet support for TMS Aurelius in the web client. TMS Aurelius uses Delphi compiler features that are not yet in the pas2js compiler. 

Did you look at the XData web client demo? This shows what can be done today with the XData web client dataset.
Ah, ok.
I thought XData meant that there was Aurelius also.
I'll put my project on hold until there is Aurelius support.
I will go back to the demo's first and start there.