dereksmithweb

No worries.
Great. Will be waiting for @swissspidy reply.

Im not asking this – sorry if you got me wrong.
Im asking where does rendering occurs in order to go there and set an IF statement like
if the request includes a 404 page, show up the new template, using is_404() , and then requiring 404-template-amp.php

Since classic mode is not providing any issues to us, we would love to keep it.
Moreover, we have eliminated all validation errors by hand.

However, Im not sure in which file a rewrite should occur.
Can you please elaborate?

I tried this mode, but moving my templates on the /amp/ folder returned posts with various errors.

Seems like they need rewriting. Is this the case, from your experience onto a hybrid mode?

Thanks again for your answer.

So it seems that I need to stay in the classic mode and implement only a 404 page for this purpose, since rest of those valuable features (category etc) are outside of the scope of this website.

Is there any chance to do this by staying at classic mode? Even if it involves lots of work, from your experience?

Can I have classic mode for posts and transitional for 404 ?

@jamesosborne first of all thanks for your prompt replies and your awesome support so far.

Unfortunately, my theme is a custom one. I just updated it to the latest version preserving my custom templates.

The mode is at classic!
If i change to Transitional mode, amp view on single posts is a mess, my custom templates are ignored.

My AMP settings show my custom post types aswell, but thats all I see, no type check (native etc).

I dont understand why I cannot use a 404 template in this version. Can you please elaborate? I thought that a condition check is_404() would be all I need to point the rendering onto a custom template.

Im using a customized version of it.
In the option fields, there are no modes to select, only post types and unfortunately, updating is not an option.