High RPC thread number on a CAS exchange server (v2010) after upgrading from v11.1 HF3 to v11.3 HF8

Hi,   After upgrading a VIPRION 2400 from v11.1 HF3 to v11.3 HF8. Outlook client suffers from many disconnection. After coming back to the version initial, this disconnection disappear.   On th...