IMC Rating: You will need to take the theoretical examination again; however, your previous IF time still counts. Thus you will need to refresh your IF prior to the test, but there are no minimum hours requirements. See LASORS Section E3 and Appendices to Section E.
Night rating: No such thing. It’s now a ‘night qualification’. There are no credits for IF in the required syllabus of training for the night qualification. See LASORS Section E4.