I have also seen that model. It is probably a Di. Since om the model it says Di and I have seen a Swedish documentary where they mention the JA 37D and the Di variant and this documentary was made in 2001, same year as this airshow. However, flygvapenmuseum says that 37431 and an other Viggen was modified to Di in 2002 but it is possible that 37441 was an early modified one too. Also, may I ask if you know if the individual 37444 had Di or D written on its left intake? I saw the 2 pictures of it on the trip report but its only from the right side. It said you had the copyright to that photo too so I felt I might as well ask here too. Sorry if something was formulated weird in the comment, English isnt my first language.

I've looked at the original photo, but unfortunately its to hard to tell. I've seen a model of this particular aircraft, where it says Di. Written very close together, so it could be Di.

Very nice picture! If I may ask, does it say JA 37D or Ja 37Di on the side on the intake? It isnt super clear.