Soanr local documantation

The PDF's cover all the stuff thru December.  The local help file will have ripple editing if you have updated the documentation file in the CCC under Sonar.
 
Also the Tech+Music magazine for May that Craig Anderton puts together has a lot of coverage on ripple editing.
 
The reference PDF is the go to book on Sonar.  Don't skip using this for complete coverage. It will probably be updated in December 2017.

Im going to go out on a limb here and say you haven't gone in to Command center and looked in the right spot for an update to local documentation.
New Features:
Mine says June 2017

Historically the reference guide was created after an update or two for each major release based on the help file at that time. After its release, it was not updated until the next major release. With the current release schedule the reference guide appears to be on an annual update schedule. The most current documentation is on the web. The chm file installed in the same directory as the reference guide is updated monthly.
 
The user guide is a fairly static document. AFAIK, it is not on a regular release schedule.

I seem to remember some confusion between the PDFs. I think the offline help is a completely seperate thing to the reference guide and getting started file. The online manual is much easier to navigate IMO.

Remember in the 80's when we complained about the demise of paper manuals with software? Seems like a quaint anachronism now. Things change fast, so many vendors don't even provide local documentation at all anymore because it's so hard to keep it up to date. 
 
I just checked here. SONAR.chm is only a month old and CCC says it's up to date, but doesn't mention ripple editing. I'm guessing it's just an oversight. The online documentation covers it, though. If your DAW is online, make sure you have the "Always Use Local Help" option turned off (Prefs -> File -> Advanced).

Seriously? This surprises me. I would rather not have to get help online, have always used the local Reference Guide PDF as my master document for help and "reference".
I assumed with the large size of the Command Center Local Documentation downloads every month that all references, guides, help files, etc were being updated.
That's pretty disappointing. it just took me hours to figure out an old interface feature is gone (still listed in Ref Guide) and a new interface feature has taken it's place. As annoyed as I am with the change, would certainly have been helpful and time saving if my Ref Guide wasn't outdated and i was looking at current information!