S2 or not S2

So, with Homeseer products you still avoid S2. I'd love to use it but have been bypassing it when adding devices to Hubitat when prompted.... from previous experience.

Now, I see this in the log.

"Z-Wave device id: 15 failed S2 bootstrapping - - Bootstrapping was successful - the device needs to be excluded then included again to use securely."

Is S2 actually OK on Habitat??? I've also read that there are problems when you have mixed devices S2/S0 on networks that it slows them down,

This one is historically a big deal for me. I'd love to be adding everything I can S2.

Please confirm or deny :grinning:

I have a C8, and I've put every ZW device I can on S2 (I still have a few 500-series devices that obviously can't). No issues at all.

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S2 works fine on Hubitat.

That said, there are probably 3-5 devices I know of that the DEVICE doesn't work well on S2... On some devices it is only on certain device firmware versions, on some it is all versions.

But if the device works properly with S2, it should be fine to use S2 on Hubitat.

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Awesome...I have about 100 physical devices .... maybe 60% are S2 capable... this is great news!

This has been debated a bit as you will find many users that say don't use it unless the device is a security perimeter device like security sensors, Doors, or garage door. Then there are those like those above and myself that don't see any reason not to.

Generally speaking S2 shouldn't be a problem if the device supports it well. Security on zwave got a bad rap with S0 which is very chatty.

Those that will argue you shouldn't use it will likely say it adds extra load, but that should be negligeable.

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Can you let me know that list? Thanks!

one for sure is a Zen25 from Zooz

GE Fan Controllers definitely had an S2 bug at one point. Haven't tested in a long time, and haven't looked if there is a firmware update.

I tend NOT to use S2 for things other than security devices (locks, mainly) and testing/driver development, so my info may be getting stale.

I ran mine on S2 for a while as a test, worked fine for me. Also the 2.10 firmware has two bugs fixed relating to S2, so my be totally fine now.

That being said, I would do any sensors you can on S2 for better transmission error checking.
Switches are debatable, probably wont hurt anything but also not a lot to gain either.

One thing to also note, if you plan to use direct associations at all, both devices must be on the exact same security in order for it to work. This is where the devices talk directly to each other. Rules on the hub can usually do the same thing between devices, and it works no matter what the security is.

There are folks like Hydro who use S2 and don't have issues, others (like me) who avoid it except w/locks as I prefer to avoid the additional messaging from S2, just on general principle that I don't care about security on things like sensors and my Z-Wave blinds.

Some devices can benefit from it as S2 has additional command processing (I can't remember the phrase that describes it) that can help ensure that S2 devices are processing commands/reporting status back accurately.

Thanks...but not sure if I followed one thing since I'm a newbie to Habitat.

"if you plan to use direct associations at all, both devices must be on the exact same security in order for it to work. This is where the devices talk directly to each other. Rules on the hub can usually do the same thing between devices, and it works no matter what the security is."

You don't mean hub to device, right? You mean one device tracking another...in HS4 that went thru the hub. IE I have a dimmer inside with no physical connection to it, but when I set it to say 50% HS4 would track that and set my patio lights to 50% ...which is physically connected to a switch in the garage.

I believe he's talking about this type of option in Z-Wave device drivers:


When you create one of these association groups the lights will turn on/off w/each other when one of them is turned on/off. Requires using the same security on each device (and I did not know that).

As he notes you can do this using HE apps - I have an RL automation that turns five switches on/off together when one of them is turned on/off.

Correct, device to device (bypassing the hub), it is called direct associations and is a Zwave feature. When you have a flexible hub it is rare that you need associations but some people are dead set on using them anyway so just wanted to warn you in case you were one of those people. There are a few use cases with Hubitat where the associations are needed or work better than a hub rule but its not often.

Awesome. Thanks for the clarification!

Except for door locks, I never employ S2.

But I do wish the Z-Wave Inclusion process for Add Devices would ask beforehand whether the user wants S2 security if offered by the new device.

Can't tell you how many times my screen timed out because I did not see the "Use S2?" prompt further down the page, during which I thought I had to wait for the countdown to reach 0.

Use Smart Start, scan the code, tap on the device entry to set the security. Then turn the device on. Thats it.

Doesn't it still look like this (I haven't had to include a Z-Wave device in ages so I don't know if it has changed), on a computer, with the security question/buttons right at the top? Or are you maybe talking about the screens/flow on a phone?

That is the non SmartStart way. If the device has a qr code SmartStart is a option. It is common on zwave 700 devices, but not before.

Yes, and I've included devices without security every time.

Even my 200 series (500 series) Homeseer dimmers have a QR code and support S2.

My main point in all of this really is I want to do the cleanest initial setup I can. I already have about 40 devices moved over from HS4. I'd much rather factory default the Hubitat and start over if it was the better thing to do long-term than start out wrong.