As per my information, you can not update all the listings at once. The process of updating the listing is as follows:
1. Sign in at bayut.com
2. Click on "Property Management" Section (You can view all of your listings over here)
3. Click on "Edit" button under "Control" Listings will be opened
4. Submit your listings after updating
You can update a few features in all listings in a single go.
Once you have logged in, under the profiles tab click on user profile. Before the modify button, you will notice a check box indicating: Update details in all property listings.
Click on it and update the relevant details in a single go. Property features like description, price and location etc cannot be updated in one go.
Hope this helps and let me know if you are not sure about anything.