Congrats on the promotion(!), but as others have stated I would be cautious with how you word your update.
Obviously, things will differ company to company based upon the nature of the product/service offered, the maturity of the research, amount of funding, number of employees, etc. I've been working with a biotech start-up and have been on its research team since it was founded. During interviews I was usually asked if I would still continue to work with the start-up (no), if the company knew I would be leaving (yes; I had an LOR from the CEO), and what I was doing to ensure my departure would go smoothly.
In fact, since the new year a majority of my time has been spent on ensuring this transition goes smoothly, even though I'll be leaving ~5 months from now. When I start med school I am not going to be able to flit back to the lab and walk my coworkers through my old experiments. When writing an update, let them know how you plan on wrapping things up nice and tidy with a bow on top so you won't find your attention drawn back to your old job once med school starts. N=1, but like
@Overanxious recommended, in my updates I reiterated my end date, the new responsibilities/projects I had assumed, and my plan for wrapping up such projects/training my replacements without leaving a knowledge gap in the company following my departure. Good luck!