https://www.native-instruments.com/en/specials/komplete/komplete-12/
 
It looks like the rumors were true.  New Kontakt 6, Massive X coming in Feb 2019, to be included.
 

• Includes KONTAKT 6, TRK-01, DISCOVERY SERIES: MIDDLE EAST, SESSION STRINGS 2, MOD PACK, and 10 Expansions
• Save over 85% of the combined cost of all included products
• MASSIVE’s long-awaited successor arrives February 2019. Buy KOMPLETE 12 now, and be the first to get MASSIVE X via free download on its release

Looks like you posted as I was creating my post.
 
£159 to update from K11  (regular Komplete).
 

I've been sitting on K9U, waiting for Kontakt 6. About frickin' time.

$399 to update from KU 8 - 11 to KU 12
 
Seems like a good price. Does anybody think the price will be better or is it best to grab it now?

They will put the upgrades on sale but it might not happen for about a year.

Looking at Komplete 11 Ultimate.  It was announced start of Aug 2016.  Shipped start of Sept 2016.  Upgrade price from Ultimate 10 was $399.  That next summer, June 2017 they offered it for $199.50 in their Summer Of Sound sale.  So about 10 months from announce date, 9 months from ship.
 
 

I wish they would change how they market Komplete Ultimate, I mean, NI adds a few new libraries to Komplete and markets is as if you're getting a whole new package.
 
I would rather simply buy the new stuff separately if I want it. Why market stuff to me I already have?

As always, I will be waiting for the first true discount price. They suffer delusions of  grandeur every new release...
 
Don't get me wrong, I love a lot of what I see there, I wouldn't go lower than the collectors edition now. But... wow, that's a steep price for me, with so much invested in older versions over the years. I've skipped other versions before though to save more too.

I'm holding off as well. Kontakt 6 and Massive X are bound to be completely bug-ridden at first which will make working far more difficult so I will at least wait till it's considered stable before I hop in. I'm really not all that impressed with what I see so far anyway. No GUI update on Kontakt, nothing to make the user end better, no freaking scaling because Bitmaps. >_<

I still haven't fully explored K11U.  I'll happily wait for bug fixes and sales.