Sorry for the late reply.
I had some nasty encounters with this device.
- Other cats would come in and mark our furniture with their urine. Flap was in normal day mode.
- The foreign cat would be able to come in but not get out when in night mode. It destroyed a lot of plants.
- The cat also fought my cat, leaving me with vet costs > EUR150.
I emailed them, and asked them if the flap could be reporgrammed, so when a foreign RFID is read, the device would lock instead of not respond. That would prevent a foreign cat from pulling the flap open with it's claw/nails.
I got a response to the effect that it was a good idea but I would need to sign all sorts of releases, then they could incorporate the idea.
In the mean time, the flap is not function properly when a wind pushes against the flap. So, in stormy weather, the flap would open, but never close.
So, there is no such thing as a cat proof, wind proof cat flap on the market today. If someone has homebrewed something, I'd be glad to hear. Reverse engineering a commercial product is a dangerous route to go. Otherwise, an open source public project would be something I would like to participate in.