Going to plaster with gypsum, is the substrate ok?

[Åsa]

I am going to plaster the walls in an old bathroom located in the basement (the house is from -39). Previously, there were tiles on the walls that we have taken down, see attached picture.
Can I prime directly on this surface and then plaster with gypsum, or do we need to remove everything so the walls are "clean" from previous surfaces (the yellow seems to be some kind of paint or similar)?

 

[Patzie]

I had rented a flex (concrete grinder) with a blade for paint/glue residue and gone over the wall so the plaster adheres better

 

[HSP]

If I were to sand, I would have found out if there is asbestos in the fix on the wall beforehand.
Gipssackel/putty is probably not suitable for basement walls.