Before downloading, you must confirm your hardware version. TP-Link routers often have several "versions" (V1, V2, etc.) that use different software. Look at the of your router. Confirm it says Archer C5(EU) Ver: 4.0 or similar.
The Archer C5 V4 is a legacy (AC1200) device. As of 2024, TP-Link no longer releases security patches for this model. For better security and Wi-Fi 6 features, consider upgrading to a newer router (e.g., Archer AX Series). tp-link archer c5 v4 latest firmware download
For those who found themselves abandoned by official support as the router reached its End of Life (EOL) Before downloading, you must confirm your hardware version