Which two characteristics should a collaboration engineer be aware of before enabling LATM on a Cisco Unified Border Element router?

Which two characteristics should a collaboration engineer be aware of before enabling LATM on a Cisco Unified Border Element router? (Choose two.)
A. Box-To-Box High Availability Support feature is not supported.
B. Configure LATM under a voice class or dial peer is not supported.
C. SIP UPDATE message outlined in RFC3311 is not supported.
D. Codec transcoding between LATM and other codecs is not supported
E. Dual tone multi-frequency interworking with LATM codec is not supported.
F. Basic calls using flow-around or flow-through is not supported.