How to texture-paint individual pixels In 2.79 I can draw individual pixels by setting the brush size to 1px, like in this example (16x16px image):

Starting from 2.80 the drawing produces extra pixels:

As you can see the antialiasing is disabled, I also tried to tweak all the other settings, but wasn't able to achieve 2.79 behavior.
Starting from 2.80 to NOT produce extra pixels, you can change brush falloff graph in way shown on the gif above.
Make a sharp transition from brush center to it edges.
As you can see radius is setted to 1px, Anti-Aliasing is disabled, 4x4px texture size.