Hi ​@Kesavan16, your phone model is not VoLTE compatible, so you may experience issues as your phone can only connect to the 3G network for calls. You can find a list of VoLTE compatible devices here https://www.koodomobile.com/en/help/volte 

Hello Georgio,

My mobile model is XIOMI Redmi Note 10 Pro Max and I can see option as “Use mobile data during VoLTE calls on the SIM”. Is that fine?

So what is the recommendation? Do  I need to buy new mobile? If your answer is Yes, I will switch it to other network.

No, that option is the manufacturer firmware for use in its destined market. It doesn’t mean that your phone is compatible with VoLTE while using Koodo network. You can find more information about compatible devices here https://www.koodomobile.com/en/help/volte

Dear Georgio,

I can find some compatible devices. My question is if my device is not listed in the list. do I need to buy new mobile?