NEW DELHI, July 4 -- India's government has spent years threatening to ban messaging apps that do not comply with its demands. This week, it tried something different. Instead of threatening to block Telegram or Signal again, the Ministry of Electronics and Information Technology sent formal notices asking both platforms why they should be allowed to keep a specific feature.

The feature in question is usernames, the ability to create a handle that lets other users reach you without sharing your phone number. Telegram has offered this for years. Signal introduced it more recently, as an optional alternative to phone-number-based contact. On Thursday, MeitY asked both companies to explain why the feature exists, what risks it creates, and ...