https://articlescad.com/fit-a-....cat-flap-in-a-upvc-d
Cat flaps are an excellent way to let your pet leave and come whenever it wants. You can select a locking flap to keep other animals and cats from entering your home. Installing a cat flap to the bifolding door is feasible provided that the door is made from toughened glass. The frame should not be rotten or damaged. The process is similar to installing one on an old wooden door or uPVC. Easy to install Add a cat flap on your bifold door, allowing your pet to go in and out of the home without having to open or shut