Note to Alexandria Hypatia is a written note found in Dishonored 2.
Dear Alexandria, I've tried to take care of your plants the best I could. I worry, though, I haven't heard from you in a long time. Are you alright?
I am still holding onto your key, let me know when you'll need it back.
The note can be found under the door of Hypatia's apartment during the mission Edge of the World.