Only on 700-series controllers. I know they work fine on 500-series controllers. Hopefully, while this release is beta tested, others with these devices (and other "troublesome" devices) will evaluate their long-term function and stability with 700-series controllers.
I have seen a sharp uptick in the number of route changes on a different (non-Hubitat) 700-series controller I have with 7.17.1 - no ill effects from this, but that test mesh is relatively small.
Another good news from Zooz support about firmware update:
"Home Assistant users confirm it fixed any issues they were having with our 700 Z-Wave sticks"
I have the external antenna upgrade on my main C7, however, I still have a couple of lights that respond slowly, despite being directly connected to the hub and having 100k connections.
So I’m really looking forward to this firmware upgrade!
LOL...neighbor had two daughters, the sounds of teenage agony that came from his house were scary. Two boys for me, best way to go. 
I'm in the beta and running the new Z-Wave stack, and I'm optimistic. I have been able to run a full-hub Z-Wave repair w/out issues, and I've had some initial speed improvements.
These beta updates here have me excited for 2.3.1! These and other hinted-at improvements make it seem like more of a 2.4.0 kinda deal, but I'll just be happy to have it when it arrives 
I have the beta firmware update. I literally just started what for me personally is the ultimate test - I'm pairing my old Zooz ZSE40 4-in-1s (500 series) directly to the C-7. It's VERY early (like, I paired it 2 minutes ago), but so far, it's already promising:
Paired on the first attempt with C-7 interface (i.e. NOT a Z-stick) - it paired automatically with no security.
I have a total of 5 of these and will slowly introduce them to the C-7 over the next week and we will see what happens. If you have no idea why this is a "test", just search the forums for a description of the kryptonite that these things were to the C-7 (yes, even when paired without security using a Z-stick).
With the fw update I was able to remove the stuck device in the ZW db (difficulty: NOT a ghost!) which means I do NOT have to reset Z-Wave and re-pair a ton of devices..
Still getting a network busy or two when doing funky things but even those don't seem to impact the system as much and recovery is quicker.
Pictured @danabw showing us how to do "Funky Things" the proper way:
I have had 3 of the ZSE40-500 running for a while and no issues. Check out my custom driver if you have 32.02 or greater FW and want easy access to all the parameters.
There is also a new firmware I was sent (32.12) to test which REMOVES the motion notification from being sent every 8 seconds, it only reports motion start and motion end. This should greatly reduce chatter in busy areas. I asked Zooz if it was for the public yet but they have not replied.
Interesting. I just sent zooz an email asking about the new FW. I tried repeatedly about 2 years ago to get these sensors working with the C-7 (including pairing with a Z-stick), but to no avail. They would pair, but I'd have to reboot (Z-Wave Restart) literally once per day and even then the mesh didn't work reliably. I ended up just picking up a C-5 hub on ebay as that was cheaper than buying new sensors. I'd really like to consolidate my Z-wave into 1 mesh on the C-7 though, so if this whole experiment works, I'll be able to do that.
That’s not a skill you want to lose. You should do it anyway to keep in practice.
Dammit...I could have sworn I burned all the copies of that picture. If my wife ever sees that it's over.
[Holds a lighter near his laptop screen] Burn, dammit, burn!!!
Was this just for the 500 series? All my 500 series ZSE40s are on firmware 32.02 like you mentioned, but my 700 series ZSE40s are on firmware 32.32.
Yes, the ZSE40-700 already has this fix from the start, it only sends reports on the first motion active then again for inactive. The 500 model with 32.02 will send notifications every 8 seconds during active motion which was thought to be contributing to the mesh problems it was causing. Even worse, by default it sends TWO alerts together, one as a BASIC command and one as a Notification command. So after much pleading Zooz delivered a fix for the old 500 model.
Interesting.. 7.17.2 includes this on the fixed issues list:
ID # 750117 Large network becomes unresponsive using 700.
Yeah the problem is always that they don't specify which component fixes that particular issue. Is it the firmware? Is it the plaform? SerialAPI fix? Is it a specific app? Etc.
But I am all for them fixing things. 
True.. and it's not clear if solving that issue requires updating all 700-series device's' firmware (not just the hub) to the 7.17.2 SDK level.
Is it likely that the wait to release HE 2.3.1 is more related to the Z-Wave SDK, or just working out other improvements to the software? I am asking because the improvements to the SDK would seem to help more Users than any additional improvements to the software functionality.
There is more; they have publicly commented on some upcoming features, including some Rule Machine enhancements. I can't remember what else is or isn't public except that and the fact that they're also testing the Z-Wave firmware update, but there's at least that.
Download the Hubitat app
