Its known already by us "older" CSers.
When the 6900 was at the end of its life some later models were released with features that became standard on the 6910s.
They were still sold as 6900s and the features were not documented.
It was only when a few users went looking for them, after the release of the 6910s, that they found them.
Some repaired 6900s also were upgraded before being returned.
Lately weve seen improvements to the group handle and group head design.