@Dp12     @Roxin 

Thank you guys for bringing this up, and we are sorry that this C20 (INWISP) is a customized version for the local market, there is currently no newer firmware update for it. As we suggested earlier, if you bought this C20 from your ISP, you would contact your ISP directly to ask for the support or firmware.

However, if you bought it from a local reseller or retailer and you do encounter an issue with the current firmware, we can try to do some troubleshooting and check if it will help:

1. Who is your ISP and what is the model number of your modem? What kind of connection type on the C20, Dynamic or PPPoE?

2. What is the download/upload speed you can get when you connect a computer directly to the ISP modem?

3. Without any other devices connected, connect one computer to the C20 directly and go to speedtest to run the test for 3 times and show us the screenshots of the test results. BTW, simplify your network layout if there are other routers or RE in your network, just leave the modem and the C20 on, disconnect other devices and run the speedtest.

And please tell me the wired link speed at that time, how to get that? You can refer to the below link.
https://www.tp-link.com/en/faq-2265.html

4. Please check if there is any QoS or bandwidth control setting on the C20, if there is any, kindly show me the setting page, it is suggested to disable it to give it a go.

5. You can refer to the below instruction to narrow down the issue as well.
https://www.tp-link.com/faq-2170.html

Have a nice day.