Most projects currently use revision 2010-09-24 of ietf-

-types, defined in RFC 6021, which is deprecated by RFC 6991. Some products, such as Tail-f NSO have moved on and use the current 2013-07-15 revision of the models. For interoperability, and for not using deprecated models, we should upgrade, if possible in Boron timeframe.

Mailing list thread with further info: https://lists.opendaylight.org/pipermail/release/2016-June/006759.html

[I filed this with lispflowmapping for lack of a better place, but this applies to all projects]