...I just booked 4 nights in London for Oct 1 and it charged me just above 50% of the total and then will charge the rest 2 weeks before the trip - no extra fees. They say they'll send a notice about the rest of the charges 3 days before it's to be charged.
Just thought I'd mention because I know sometimes people don't like having to pay what could be a large amount of money months and months before their holiday.
https://www.airbnb.ca/help/article/1696/pay-less-upfront-terms