Apple has now released this update to High Sierra. (see links below)

As a side note, I was advised of this update through an email (just received prior to this writing), from the developer (Maintain) of the 3d party utility, Cocktail (11.1 is current for High Sierra). The email advised that this Apple update (10.13.2) includes "a permanent fix for the root password security flaw" and the email also provided a link to Apple's Combo Update, which the developer, Maintain, recommended using.

10.13.2 Combo Update

Apple Support - Security Updates

Yesterday, in the Apple Store I found a pending update to "MacOS 10.13.2 Combo" recommended for all users. I had just installed MacOS 10.13.2 the previous day, but that was the regular updater. In a little over 24 hours the App Store had presented me with and installed…

• MacOS 10.13.2 beta 6
• MacOS 10.13.2
• MacOS 10.13.2 combo

I am a bit curious about the entire sequence of updates and why, for the first time ever the combo updater showed up in the App Store

I just upgraded from 10.12.6 to 10.13.2. It took about 40 minutes and all seems well so far.

What prompted your decision? Your iMac is identical to mine and I was feeling that the cons outweighed the pros.

Security issues were my main concern. Although Apple will support Sierra for the foreseeable future, eventually that will stop. Of course, I backed up everything before upgrading so that I could revert easily. I had previously checked https://roaringapps.com for app compatibility, so I knew that, with the exception of Cocktail and OnyX, everything would work. I updated those two apps after upgrading the OS.

Speaking of security, Apple releases iOS 11.2.2 for iPhone and iPad, supplemental macOS 10.13.2 security update I'm sure that Apple will also release one for Sierra, but it's nice to know that I already have it.

The Safari update released at the same time as the other two updates says it is a patch to mitigate the Spectre vulnerability in OS X 10.11 and macOS 10.12.