I have built 3 different versions of cat gate in our old house and recently we moved, so I re-used the old frame from Cat Gate v3.0 and upgraded to this version.
The design is to minimize the damage to the house but it has to be structural stable. So, I anchored to the wall on both sides – yes I had to rip one drywall and added 2×4 for support, drywall anchors are too light duty. Note that there is nothing mounted on the hardwood floor (only felt pads are used). In case we need to sell the house, the only thing need to do is to patch the drywall, easy enough.
The door is fixed to the frame but the two panels (windows) are removable, I modified the plastic mirror clips to hold them in place.