10 SMS Restriction on Lumia 640 LTE

[Windows Central Question]

I bought one Lumia 640 LTE single sim (RM-1073) device from Ebay in India. The phone has been duly officially unlocked and I am able to use the same. It is an excellent business executive device. I have only one problem. I understand that in USA AT&T has a restriction of maximum 10 sms in a group and because of that I am not able to send more than 10 sms at a time although the phone is unlocked from AT&T. Is there anything that can be done to resolve this issue in India so as to remove the restriction not applicable to my operator (Vodafone).

 

[shmsnh]

If possible, try to flash it with a country variant ROM.

To be honest, I don't have any experience with carrier-locked phones, so I do not know what the problem could be.