Hey Sébastien,

I am really sorry for the delay of this reply as it is a weekend for us here.

Unfortunately that was not possible is because those blog post was created from 3.9 version using Joomla default editor.

In other words, If the blog post created with build-in composer, then you can't edit the blog post using Joomla default editor is because we prevent the existing blog content original styling and the Joomla default editor do not know how to render the built-in composer inside the block feature.

That's what I thought, but I had the small hope there would be a workaround I did not think of, or some migrator or something!

No prob. and no prob for the weekend, I know. Hope it was nice for you!

Hey there,

Yeah, we actually tried and there's actually no "real" way to properly distinguish what your HTML code does. For instance, we could convert videos into it's respective youtube / vimeo / video blocks but what happens when people uses "iframe" or "embed" codes from video providers. There's no way to detect them all

Nevertheless, we'll keep trying!