Attended a webinar on Thursday and as per MIT :
1. R1 applicant will heard back from MIT by the end of December, but what they hear can be; their applications will not be taken further, or they cleared the initial assessment and their interview will held in Jan/Feb etc.. In other words the answer might not be a clear cut yes or no.
2. R2 international aplicants will also start getting invites by the end of December
3. Those who applies in R3 before end of December also might receives invite to be interviewed at international locations (provided they apply before the travel schedule of adcom is finalized). So if there are any international student who missed R2, they should apply ASAP if they want to avail an interview outside USA.
Cheers