Hello @mtsig!
The short answer is no, unfortunately we haven't had preparations for a physical book or eBook about Ext.NET 7.
Our official book release was
back in December 2012 and the book basically reflected Ext.NET 2 and have been useful for Ext.NET developers down to version 5, where the syntax remained more or less the same.
While a lot of concepts should have remained, Ext.NET 7 is a pretty steep technology change from its predecessor version 5 (and that's one of the reasons why we skipped not one, but two version numbers between releases!). So the book should still be very useful, but many WebForms-specific tricks won't be applicable to Ext.NET 7 that uses Razor Syntax in traditional Html Helpers syntax (
which our MVC 5 examples uses) and the new
Tag Helpers to compensate the loss of WebForms (and which most of the
new examples explorer uses).
Hope this helps!