That's an "Open" question.
In most of the boats... '99 was the last year of the ROTAX 2-stroke. The exception was the Sportster LE. I think that one got into 2004. In 2000... they switched over to the Merc 2-stroke engine. In 2005, most of the boats finally got the Rotax 4-stroke engines, with the exception of the Islandia. That one switched over to Rotax 4-strokes in 2006.
That's in the USA. I'm not sure if they sold them in other countries longer or not.