According to the versions you shared above, your hub is running 718. If you didn't downgrade to 715, yet, then follow these steps:
Go to: yourHubIP*/hub/advanced/installZipgateway715
Reboot the hub from Settings
Go to Z-Wave Details page, then select Update Firmware to install "Z-Wave and Z-Wave Long Range 700/800 SDK 7.18.1.0"
Go to: yourHubIP*/hub/advanced/installZipgateway718
Reboot the hub from Settings
If you already downgraded to 715 and your hub still reports 718, you may need to reboot the hub, before continuing from step 3.
NOTE you must update to platform version 2.3.8.122 first, otherwise, if you are already running any of the previous 2.3.8 versions, you will be facing a permanent loop, as the hub will auto update to 718 as soon as you reboot after downgrading to 715. This has caught a few users by surprise.
Thanks! This is super helpful. I see the link to the KB on this as well, it might be helpful for others to include that link on the release notes for 2.3.8.122 as well?
Appreciate the assistance. Update is running now, hopefully it goes smoothly.
Whew, I scanned right past that. I would include a note under the section where you Change from... - because that's the instructions for me, a C-7 user who doesn't know they're experiencing a bug.
I didn't click into the link under bug fixes, because I didn't know I had a bug, and so I just assumed the update would fix whatever it was that was referring to.
They do not update the Z-Wave firmware for no reason. All of the updates pushed out for the C7 were to fix critical issues that impacted performance. There were 2-3 updates and I remember each one made noticeable improvements over the prior.
So if you use Z-wave and have a Z-wave update available I would highly recommend getting it installed.
I guess, I'm just coming from the position of 'if it ain't broke' so-to-speak, and rolling back/re-up dating etc, makes me nervous as I've been burned so many times in the past...
I'm assuming this firmware will never become updateable in a future update?
It is updatable, you just need to downgrade the SDK first so it will work, which is a very minor procedure. I am guessing it will not work again without the steps listed. And it (the old z-wave firmware) is broken, very badly. You will see significant z-wave improvement. I cannot recall anyone who ever had issues caused by the z-wave update so it is very low risk. The SDK downgrade / upgrade is just software so even lower risk.
Apologies, I mean at this point in time I click update in Z-Wave settings and I'm told my current firmware cannot be updated. The solution is, follow the process you've outlined above to downgrade the radio, then update.
But essentially, I'm nervous about downgrading then updating (probably silly, I know). As a consumer I've learnt sometimes just to wait for official fixes rather than 'tinker'. Here I was hoping that a Hubitat FW update would allow me to update my 7.17 radio to 7.18 in the future, if so, I'm happy to wait.
But maybe this update is entirely detached from Hubitat Firmware and it's a Z-Wave alliance issue going from 17-18, in that case I'd like to know that too.
Unless I'm just over thinking this entire thing and shouldn't be so nervous, after all I have cloud and local backups!
Ok, well, I just followed the official instructions for my C7 and now my zwave is 'unresponsive'. Awesome. Anyone have any guidance on addressing this issue?
Someone else who had an unresponsive z-wave was able to fix it by running the /hub/advanced/installZipgateway718 endpoint again. Keep running that until it tells you that it is already updated, reboot, then run it again and make sure it stuck.
Thanks. I went back to the 715 endpoint and it started working (just did this before your reply) and when I did the 718 endpoint in remained working. So yeah, looks liek that's the deal.
Yup I would guess the 718 update failed last time and got the radio stuck. Same as what happened to the other person. Luckily that part is easily recoverable.
Change from... 
