There are some 'requirements' I hesitate to call them rules for the IMC revalidation. During the 25 month period you should have carried out a pilot-interpreted approach to the satisfaction of an instructor qualified to teach applied I/F. This should be signed for in your log book. Then on the renewal test you would be expected to undertake a different pilot-interpreted approach. However if you haven't done a supervised approach in the 25 month period then the examiner will ask to see two pilot-interpreted approaches.