In addition to the bug fixes, CIFS provides the following enhancements and changes in OES 2015 and OES 2015 SP1 March patch:
When a client-server session is established over SMB2, if the server configuration is changed from SMB2 to SMB, the server now responds only to client negotiate request over SMB and not SMB2. For more information, see Section 11.1.1, Interruption in access to the CIFS shares from Windows clients upon change of server dialect from SMB2 to SMB or upon cluster resource migration.