Internal focusing, not a trombone lens. Interesting. I wonder if it will be a real 400mm or the good to 350 like the old one? But a much better mate for the 70-200 design, just more range.

Minimum focusing distance dropped to 3.2' / 1.0 m (from 5.9' / 1.8 m)

http://www.bhphotovideo.com/explora/photography/news/canon-announces-updated-ef-100-400mm-f45-56l-ii-usm-lens?cm_mmc=EML-_-Newsletter_Newsletter-_-141110-_-BannerT_Explora_Canon-EF100-400L-ReadMoreBttn

A lot of the updates were needed but not much mention of image quality.  I use the 400mm 5.6 because the sharpness was much much better than the old 100-400mm.

Sob! No way could I justify that nowadays. 

I'll wait to see some reports on image quality first. If it's an improvement over the current version, I may be tempted to replace my old one. The reduction in minimum focusing distance plus an improved IS sound very nice.

Some samples here (no 100% crop, sadly    )

http://www.canonrumors.com/2014/11/ef-100-400mm-f4-5-5-6l-is-ii-sample-images/