I use gmail for something similar. Sometimes it's a direct email to me (or someone else programmed to be send in the future). Sometimes is an email to my coworkers, but it has a few notes for me, so when we continue some project in the future it has a warning like:

fake quote> We careful with the matrix M because it looks like a 7x7 matrix, but it's actually a 14x14 matrix and that makes the program too slow.

because I made the mistake now and I don't want to repeat it in the future.