WPA3 is the current Wi-Fi security standard certified by the Wi-Fi Alliance, and it changes how a device and a router agree on encryption during the connection handshake. Older device radios, especially the low-power chips used in many smart plugs, bulbs, and sensors, were built and certified before WPA3 existed, and some of them simply don’t implement the newer handshake at all. When a network is set to WPA3-only, or even to a mixed mode that offers both WPA2 and WPA3 on the same network name, some of those older devices fail to connect, fail intermittently, or connect and then drop, not because of a signal problem, but because the security negotiation itself is failing. Checking your router’s wireless security setting is the direct way to confirm this is what’s happening.
What actually changed with WPA3
Wi-Fi security standards define how a device proves it knows the network password and how the resulting connection gets encrypted. WPA3 introduced a different handshake method than WPA2 used, designed to be more resistant to certain kinds of password-guessing attacks. That’s a genuine security improvement, but it also means the handshake itself is a different conversation than what WPA2-only devices know how to have. A device that has no WPA3 support in its Wi-Fi chip or firmware isn’t being slow or unlucky when it fails to connect to a WPA3 network. It’s attempting a conversation it was never built to have.
Mixed mode: the setting that’s supposed to help, and sometimes doesn’t
Because so many older devices exist, most routers that support WPA3 offer a mixed mode, sometimes labeled “WPA2/WPA3,” intended to let both older and newer devices connect to the same network name at once. In principle, each device negotiates using whichever standard it supports. In practice, mixed mode is where a lot of the reported compatibility problems actually happen, not with WPA3-only networks. Some older device radios handle the presence of WPA3 capability being advertised on the network, even when they’re free to use WPA2 themselves, poorly, and the handshake can fail, stall, or complete and then disconnect shortly after. This is a known rough edge in how some manufacturers implemented mixed mode support in their own chipsets and firmware, rather than a flaw specific to any one router brand.
Which devices are most likely to struggle
The devices most likely to have trouble are the ones with the simplest, cheapest, and oldest Wi-Fi radios: budget smart plugs, older smart bulbs, some sensors, and devices that haven’t received a firmware update in a long time. These devices are typically built to a minimum functional spec and a low cost, which means WPA3 support, or even robust mixed-mode handling, is one of the first things left out or left unpolished. Higher-end and more recently released smart home devices, along with essentially all current phones, laptops, and streaming devices, tend to handle WPA3 and mixed mode without issue, since WPA3 support has become standard in newer Wi-Fi certifications.
The mismatch this creates is exactly the kind of thing that makes this hard to diagnose: some devices on the network connect fine, and others, seemingly at random, quietly fail, when the actual pattern is that the failing ones are simply the oldest radios in the house.
Checking and testing this
Check your router’s wireless security setting, usually under wireless or Wi-Fi settings, for whether it’s set to WPA3-only, WPA2/WPA3 mixed mode, or WPA2-only. The exact label and location vary by router manufacturer and firmware, so this is what to look for rather than a fixed menu path to follow.
If the network is on WPA3-only or mixed mode and one or more older smart home devices won’t connect or connect unreliably, temporarily setting the network to WPA2-only is the most direct test. If the problem device connects cleanly on WPA2-only and struggles on WPA3 or mixed mode, that confirms the mechanism.
Many routers let you run a second network name specifically on WPA2, separate from a primary WPA3 or mixed-mode network, so newer devices keep the stronger standard while older ones connect to a network built for what they actually support. This avoids weakening security for every device on the network just to accommodate the oldest ones.
The trade-off worth naming
Running everything on WPA2-only to sidestep compatibility problems does work, but it means giving up the security improvement WPA3 was built to provide, for every device on that network, not just the old ones. A second, WPA2-only network reserved specifically for the devices that need it is generally the better trade: it keeps the stronger standard for everything that supports it, and limits the older standard to the narrower set of devices that genuinely require it.
What this doesn’t explain
A device that fails specifically on WPA3 or mixed mode and connects cleanly on WPA2 is a strong, specific signal. If a device fails to connect regardless of which security mode you try, the cause is more likely elsewhere entirely, such as being on the wrong band or a mesh system handing it the wrong radio. If you’re not sure which category the failure falls into, the device, radio, router or cloud test is the right place to start narrowing it down.
FAQ
Will a firmware update eventually add WPA3 support to an old device?
Sometimes, if the manufacturer chooses to support it and the device’s Wi-Fi chip is technically capable, but many budget and older devices never receive that update, either because the hardware can’t support it or because the manufacturer has stopped updating that model.
Is WPA3-only more secure than mixed mode?
Yes, WPA3-only removes the older handshake option entirely, which is more secure than mixed mode’s default of also offering it, but it also excludes any device that can’t do WPA3 at all, which is a real trade-off for a household with older smart home hardware.
Does this affect 5 GHz devices differently than 2.4 GHz devices?
The WPA3 handshake compatibility issue itself isn’t tied to a specific band. It’s about the security standard, not the frequency. Most budget smart home devices that struggle with WPA3 also happen to be 2.4 GHz-only, but that’s because cheap radios tend to skimp on both, not because the two problems are the same thing.
Can I run WPA3 on one band and WPA2 on another instead of a whole separate network?
Some routers allow different security settings per band on the same network name, which functions similarly to a separate network for this purpose, but the option and its exact behavior vary by router, so check your specific model’s settings.
How do I know if a specific device I’m about to buy supports WPA3?
Check the product’s own specification sheet or the manufacturer’s support documentation. WPA3 support, when present, is usually stated explicitly, since it’s treated as a selling point on newer hardware.
Sources referenced in this article
- XDA Developers, Your router’s WPA3 security is breaking your smart home, and here’s what to do about it.
https://www.xda-developers.com/wpa3-breaking-your-smart-home-what-to-do-about-it/(accessed 2026-07-22). Source of the mixed-mode compatibility problem pattern described above. - University of Iowa Information Technology Services, WPA3 security transition, wireless.
https://its.uiowa.edu/services/eduroam-ui-devicenet-ui-guest-wi-fi/wpa3-security-transition-wireless(accessed 2026-07-22). Source supporting the description of transition/mixed-mode behavior during a WPA3 rollout.
Review interval: 12 months (WPA3 device support and router mixed-mode implementations continue to change).