|Good point, Yoli, but as I understand it, those two things aren't necessarily contradictory. I don't remember where I researched this - and it was a long time ago, so take this with that qualifier... |
I agree that the SOS only issues one type of "Authentication", i.e. an apostille. However, I believe the Hague Convention (along with many other things) deals with whether or not they participate in the agreement to accept that authentication as valid within their system(s), whatever they might be. So if a country that's not a party to the Hague Convention wants some other type of 'authentication', they're out of luck. [Of course, I can't comment on what is done in other states, but I'd guess it's likely very similar.]
I suppose it's possible that non-participating nations will just accept whatever is provided, as long as it has a stamp that looks like a notary seal. I have no idea about that, but I leave those worries to the signers who contact me about notarizing their documents.