@adamjacobmuller Appreciate the great work here. The newer firmwares have a new flag in the device discovery process called new_klap. I created a PR already that uses this flag to determine the correct transport to use during the discovery process instead of modifying the transports themselves, PR#1580.

Your method, while it works, mixes the authentication process between the two different KLAP transports and it doesn't keep a clean line of separation between them.

I just finished it recently, had to handle some issues with the CLI and making sure that all of the other devices and tests worked correctly. Just waiting on merging and a new version to get it going.

Confirmed Working ✅

Just tested this PR on two HS300 power strips that were previously failing with the "Device response did not match our challenge" error.

Environment:

• HS300 (US) Hardware v2.0
• Firmware 1.1.2 Build 241220
• macOS / Python 3.14

Before this PR: Authentication failed with KLAP v1 (md5)
After this PR: Both strips connect and all 12 outlets are controllable

Test Results:

192.168.0.120: ✓ SUCCESS! TP-LINK_Power Strip_1C73 (HS300)
  Outlets: Coffee Maker, Kettle, Milk Frother, Roku TV, Apple Player, Rice Cooker

192.168.0.219: ✓ SUCCESS! TP-LINK_Power Strip_1CD6 (HS300)
  Outlets: Tripod Lamp, Plug 2-6

The auto-detection of KLAP v2 worked seamlessly. Really appreciate this fix - these strips have been unusable with Home Assistant since the October firmware update.

Hope this helps get the PR merged! 🎉

HS300 was exactly what I built this for (nice little gadget). Hoping it gets merged too, but, it works fine for me either way :)

This doesn't seem working for my HS300s; connection succeeds, but the device class is wrongly set as kasa.iot.iotplug.IotPlug instead of kasa.iot.iotstrip.IotStrip. Because of this, I'm unable to control sockets on the power strip from a script (device.children is an empty list)

model: HS300(US)
build: 241220
on nixOS linux with Python 3.13.12

My test script:

import asyncio
import kasa

async def main():
    dev = await kasa.Device.connect(
        config=kasa.DeviceConfig(
            host=input("host? "),
            credentials=kasa.Credentials(
                username="xxx@yyy.com",
                password="xxx",
            ),
            connection_type=kasa.DeviceConnectionParameters(
                device_family=kasa.DeviceFamily.IotSmartPlugSwitch,
                encryption_type=kasa.DeviceEncryptionType.Klap,
            ),
        )
    )
    await dev.update()
    print(f"children: {dev.children}")
    await dev.disconnect()

if __name__ == "__main__":
    asyncio.run(main())

Please let me know if I can provide any more information or am doing something wrong; I'm not very familiar with python-kasa and am just looking to get this working for a larger project.

I've created a fork that patches the issue for me by detecting device type through sys_info for KLAP connections (where this was only previously done on connections using the XOR transport). I don't expect this to be an accepted solution, but it solved the issue for me and may be of some use:
adamjacobmuller@97cdd71

Hey @adamjacobmuller — appreciate the work here, this was one of the first PRs to tackle the IOT KLAPv2 auth issue and confirmed it's a real problem affecting many users. 🙏

That said, #1692 takes a cleaner approach — it selects upfront in based on rather than falling back at runtime inside the handshake. This avoids mixing v1/v2 auth logic inside and keeps the transport boundary clean (as @ZeliardM also noted).

#1692 also fixes the device class misdetection that @2myaus reported here — HS300 strips wrongly instantiated as with empty . That fix requires the sysinfo query path change in which this PR doesn't cover.

Would you be open to closing this in favor of #1692? Both solve the core auth problem, but 1692 handles the broader set of regressions with tests included. 🤝

There is already an existing, extensively tested PR that handles all of the CLI and API changes, #1580, we are working to get this implemented and a new version released soon.

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