Is there any protocols to identify what sort of document MS-408 is?

[ReneZ]

and I wouldn't dare say anything about Esperanto, Volapük or You are not allowed to view links. Register or Login to view. entropies without measuring them first

There are several good points in this thread, and this is one.
People usually underestimate how significant a change you need to a text in order to appreciably change the character-level entropy values. 

In Voynichese, entropy is almost certainly downstream of the qualitative lettering-ordering effects and whatever constraints created those.

Another good point. Entropy (contrary to age) is just a number. There is a whole frequency distribution of fractions adding up to one behind it. There are infinitely many very different distrubutions with the same entropy.