I am not totally sure if this is a problem with booking.com or with Kayak, but there is a problem with the android app that these companies use. The problem relates to the display of details for the rooms. In some cases, when you are selecting a room from a specific hotel, it will not display the details for the room, such as whether it is non-smoking, etc. This caused me to accidentally book a smoking room when I wanted a normal room, and by the time I checked the booking the night of the check in, it was too late. The hotel was not able to transfer me to a different room, and both Booking.com and Kayak.com refused to help me with this, despite the problem with their app. Beware their app, and beware their ridiculous customer service.