The site will be under planned maintenance this Saturday night 12/7 at 10 PM and will run until 10am the following morning (Sunday morning 12/8). This will update the video player that handles the interactive lectures. If you are in the middle of a video BEFORE the update it will lose the remembered progress after the update. This means (for example) if you're in the middle of Unit 2's lecture (planning to pick up and finish later, do not wait until after the update), finish the Unit 2's lecture video before 10PM on Saturday. (Same for if you're in the middle of Unit 3's video lecture, and so on). If you are not in the middle of a video there is no need to worry. This only affects people in the middle of a video and wanting to resume AFTER the update.
Feel free to ask any questions if you have any.