Posted on the Betfair forum by Betfair Customer Services….
From this time all Betfair products, including our sports exchange, casino, arcade, poker, API, community and mobile products, will be unavailable. We anticipate that the core exchange will be back up and running by 10:00 (GMT) on Tuesday 10th January, with the rest of the products available later in the day (GMT). Please note the poker site will not be available from 21:01 (GMT) on Monday 9th January 2012, until the afternoon of Tuesday 10th January 2012.
The upgrade work is being undertaken to bring long-term benefits to our customers and we will be working hard to get normal service resumed on the site as quickly as possible. We’d like to apologise in advance for any inconvenience caused, and thank you for your understanding.
Updates during the outage will be available at service.betfair.info. If you have any questions then please email our Helpdesk at firstname.lastname@example.org.