Avaloq developer

I got a call from a HR for an avaloq developer position. But I have experience in production support Engineer and avaloq is one of the many applications I work on . But I have very basic info on this application. I informed the same to HR he said whatever experience is fine just you should have worked on avaloq for 3 years. But now I'm in dilemma of what to prepare for interview . Don't want to get embarrassed in front of interviewer.