As of SDK 5.3.1 (I think) the SDK only supports TLS due to the sslv3/TLS session renegotiation vulnerability. For cDOT TLS is enabled by default but for 7-mode you have to enable it manually:
filer> options tls.enable on
If there is no tls.enable option on your DOT release then you can either (a) upgrade your Data ONTAP to a release that does have TLS support or (b) stay with SDK 5.3 or older which allowed ssl v3 connections.
Cheers, Chris Madden
Storage Architect, NetApp EMEA (and author of Harvest)