If you applied this cycle, I would send an Update letter to the School(s): Saying what you have done since you sent out your Primary and Secondary Application, also say that you are still here, and intrested in their school.
I agree. Make it a full update letter, including any other activities you continue to be involved in that are relevant to your application, and maybe fall grades (that reflect well on you) as well. Close with a statement of continued interest and maybe why that school is perfect for you. Email or snail-mail letter is fine.