If you are still using BlackBerry Enterprise Server (BES) 4, for a limited time period, there are no costs to upgrade to BES 5.0.4.
No cost upgrade
For a limited time, you can upgrade from BlackBerry Enterprise Server 4.1.7 to BlackBerry Enterprise Server 5.0.4 for free** – that's a savings of $999US.
Access to great new features
BlackBerry Enterprise Service 5 has many features that simply aren't available to you on previous versions, including improved administrative capabilities and control, enhanced monitoring and the ability to keep work and personal separate and secure on one device using BlackBerry® Balance™ technology.
A clear path to BlackBerry Enterprise Service 10
BlackBerry Enterprise Server 5 allows you to manage your BlackBerry OS devices through the BlackBerry Enterprise Service 10 management console, enabling a unified device management experience across your entire mobile fleet - including BlackBerry, iOS and Android™.