If you miss the posted deadline (1st checkpoint), you must still submit your assignments within 72 hours of the deadline in order to stay active in the course. Assignments submitted on the second checkpoint will still be graded but will be tagged as 'late'. Submission on the second checkpoint will not receive detailed feedback.
Note: Any late assignment submitted after the 72-hour deadline extension will be considered missing and will result in withdrawal from the program.
Please see Android Development - Coursework Submission FAQs for more details.