Hi,
I developed an iOS app which will do SMS filtering by following this documentation. https://developer.apple.com/documentation/identitylookup/sms-and-mms-message-filtering) I built the app and send Test Flights to different testers. All the Testers from Sri Lanka (an asian country) says filtering is working and they can see all the enabled categories on the Messages too (including iOS 26). But the testers from Mexico cannot see the categories and filtering is not working.
On official documentation there is nothing about supported countries. But I found true caller article https://support.truecaller.com/support/solutions/articles/81000406341-how-do-i-enable-sms-filtering-on-iphone mentioning it support only few countries for SMS filtering.
Currently available in the following countries: India, Nigeria, South Africa, Kenya, Bangladesh, Sri Lanka.
Our previous Categories filtering are still available for: Australia, Bahrain, Canada, Ghana, Tanzania, United Kingdom, United Arab Emirates, United States of America, Zambia
Following article https://clearstream.io/blog/ios-26-iphone-new-text-message-filtering is saying some categories are supported by only Brazil and India.
Still I could not find any official documentations saying different country supports.