About 1 month ago I bought a (unfortunately) "online book" (unfortunately not available in a print version). So from one side, then I got a link via email (which I have not opened yet). Apparently, this link is limited to 2 devices, such as mobile phone and laptop. But I only have my phone, only if I download it here and I have a new phone at some point (which will soon be the case), then I do not have the book anymore? Because I can't save it anyway, right? Otherwise I could send it on or something. And I hope it is not too late and the link is still available and not limited in any way…
And I would get a completely new phone with a new phone number. Apple ID would be the same, if that's possible if you change the phone number.
You have to clarify this with the provider where you bought the online book…
Where exactly did you buy your book?
http://www.fabiola-giunco.de/shine/
Oh, you cachet. The book is rip-off.
Anyway… It says you'll get a PDF download.
The PDF can be opened on multiple devices.
So just save PDF and watch on all your devices you have.