What does the rest of your Zigbee network look like? If you have more than 32 Zigbee "end devices" (non-repeaters, which are normally battery devices--plus every Sengled device I know of, even though they aren't), then you'll need repeaters to extend the capacity of your network. They're a good idea to have regardless, but they're a true need in this specific case. Other than that, there aren't any practical Zigbee limits.
I don't believe 2.3.0 added any Zigbee changes, so that is unlikely to be the cause. However, if you're suspicious, you can always downgrade from the Diagnostic Tool (port 8081).
Currently I have 35 Zigbee devices which are all Stengle’s bulbs - both element classic and color plus assortments. Sounds like the 3 new candle bulbs that I added over the weekend may have maxed things out and a repeater is needed now.
So you get 32 devices from the hub... if you have few other devices repeating then yep that looks like the issue... In terms of repeaters I am using the old Iris V2 outlets which are now hard to find so maybe CentraLite or Innr? Also I understand the Trådfri outlets are good, but maybe a bit weak.
Pretty much any powered device is a repeater, but Sengled bulbs and outlets are an exception. Most smart bulbs, however, are a bad idea because they don't always repeat well for non-bulbs (some people report better luck with newer ones, but I don't know any objective data), so that could be an issue if you have non-bulb devices on your Zigbee network, as many people do--and perhaps that's why you went with Sengled in the first place.
But in general, most smart plugs, switches/dimmers, etc. should all work, though there are also a handful of dedicated "repeater" devices if you prefer for some reason (like Ikea's USB Tradfri repeater), plus several DIY options like an Xbee or CC2531 with special firmware. I used to like the SmartThings outlets, which I see I mentioned in the post linked to above, but they got hard to find recently; if they're in stock again, I'd be shocked if Aeon (the new vendor) didn't raise the price so they're less appealing. The Innr Plugs seem pretty good and reasonably priced. But again, almost anything should work.
Do keep in mind that each repeater also has its own limit, often something like 4-6 or or maybe 12+ for the more powerful ones--but the takeaway in any case is that you could need more than one, especially if your network expands in either number of devices or range.
I have used several Ikea plugin outlets with good success. Recently some of them have begun to fail. They will toggle on and off repeatedly.
I'm migrating my main non-lighting network to a new hub. As I build out that system I have been using GE outlets to extend the Zigbee network. So far so good. My sensors outdoors have been solid since moving to the GE outlets.
I just ordered a couple SYLVANIA Smart ZigBee Smart Plugs to add. I have WiFi plugs connected to some small lamps but they obviously are not Zwave so I'll use these new ones to hopefully strengthen the mesh.
Maybe a stupid question but will these plugs need to be added to my Hubitat like I would with my bulbs?
I had the exact same problem the other day. I have a C-5 hub that handles only my color zigbee bulbs. I have 26 zigbee devices on that hub. I just purchased 6 new sengled bulbs and none of them will pair on that hub out of the box. I tried factory reset and they still wouldn't pair. I am using Zigbee channel 20 on the hub. I tried it on my main C-7 hub and it paired immediately. I use channel 15 on that hub. I noticed that the model number on the new Sengled bulbs is one digit different from the older Sengled bulbs that I have. I'm not sure if they changed something in the firmware. They seem to work fine on the C-7.
There is no difference between Zigbee on the C-5 vs. the C-7, so the difference must lie somewhere else. I'd add a repeater (or more) to your C-7 (EDIT: wait, C-5) to see if it helps if you want to use the Sengleds there--or even if you don't want to use them there and you don't already have any repeaters, since it's a good idea regardless.
They work fine on the C-7 they just won't pair on the C-5. It could be that 26 zigbee devices on that hub is too much but I seem to have hit a theoretical limit somewhere on that hub for sure.
There is a non-theoretical limit on Hubitat of 32 directly connected Zigbee "end devices," meaning non-repeaters. Sengled bulbs are all end devices. Repeaters can extend this indefinitely (theoretically probably to just over 65000), though each repeater also has its own, usually much lower, child limit. Range can be an issue too, and repeaters would also help with that
I will get a couple of repeaters and see if that helps. I noticed that the model number of the "new" Sengled bulbs is E21-N1EA and the model of my older bulbs are N11-N1EA (which is the model listed on the Hubitat compatible List). I'm not sure if they changed something in the firmware on the bulbs....but that still wouldn't explain why they easily pair on the C-7.... I might add that I am replacing that C-5 with a new "Black Friday" C-7 soon. It will be interesting to see if that makes any difference.
Also I am pretty sure it isn't a range limit issue on these particular bulbs. I have a Zigbee vibration sensor on the mailbox that is 50 feet farther away from the hub than these bulbs. Also they work perfectly in the same spot with the C-7. I realize that the mesh on the C-7 isn't the same as the C-5 but we are talking 15 feet from the bulbs to either hub. I tried to pair them within inches of the C-5 using a lamp also and that didn't work.
