The hotfix for MAPI over HTTP support for Outlook 2010 has been released at last.
Microsoft Exchange Server and
Blackberry Enterprise Server news, views and fixes.
Currently requiring a manual request and installation, no word on whether it will be available through any of the automated distribution methods.
(This replaces kb2899591 released in December which was withdrawn).
On the server, MAPI over HTTP requires Exchange 2013 SP1 (aka CU4) or higher. It is a new communication protocol for Exchange/Outlook communication which will eventually replace RPC over HTTP.
For the client the hot fix requires Outlook 2010 SP2 to be installed.