Not sure if this should/could be classified as spoilers or just Finnish Broadcasting Company(YLE) getting stuff completely mixed up.. But I just read news on YLE's website about Who's 50th anniversary. They are showing The Day of the Doctor with other countries on Saturday.
Any way in their description of episode they are claiming that Matt Smith will be seen on the episode with future Doctor Peter Capaldi! Later in the article they list that in the episode we will see aforementioned Eleventh and Twelfth Doctors and also Tenth (Tennant) and still unknown Doctor (Hurt).
So they are not mixing Tennant and Capaldi.. And they credit both Tennant & Smith in picture.
Here's the news article.. http://yle.fi/uutiset/doctor_who_juh...omessa/6948588
Maybe you can run it through Google translate or something..
And I must stress that this is probably first Who-related news I've ever read on YLE's website, so this probably is just mixed information.. Atleast I havent seen this even rumored anywhere.
Edit: and they edited the article.. Simple error or notice from BBC?