Checking TP-Link’s regional support sites reveals a fragmented story:
If you want to expand your Wi-Fi using TP-Link’s OneMesh range extenders (like the RE series), you need the latest firmware on the v3.20. Older firmware on this hardware version tends to drop the mesh connection randomly. tp link archer c6 v3.20 firmware
This covers finding, checking, and updating the Archer C6 v3.20 firmware, plus basic troubleshooting and safety tips. plus basic troubleshooting and safety tips.