After modifying an appointment with Outlook 2013 SP1 CU 10/14 or higher it cannot be read via WebDAV anymore

Hi,

we use WebDAV to read appointments from Exchange Server 2007 SP3 CU. When we modified an appointment withOutlook 2013 CU 09/14 we experienced that we could not query it with the filter BillingInformation<>"" anymore.

With the Outlook 2013 CU 10/14 this temporarily fixed, but reocurred last week. It does not happen with Outlook 2010 SP2 (14.0.7113.500) or other versions of Outlook.

How can we tackle this?

Thanks for any advice

John

John