Due to high availability reasons, BlackBerry will change some IP-Addresses on November 11th, 2013.
This change will affect only the “Universal Device Service” in BlackBerry Enterprise Service 10.x and the address “<country>. bbsecure.com” via port 3101. Customers who are only using the BlackBerry Enterprise Server 5.x or the BlackBerry Device Service are not affected according to the detailed information which can be found here.
