Popular messaging service WhatsApp is banning under-16s from using its platform in the European Union.
Users must currently be at least 13, but the firm is changing the rules ahead of the introduction of new EU data privacy regulations in May.
The app, which is owned by Facebook, will ask users to confirm their age when prompted to agree to new terms of service in the next few weeks.
It has not said how the age limit will be enforced.
At present, WhatsApp does not ask users their age when they join, nor does it cross-reference their Facebook or Instagram accounts to find out.
About a third of all UK-based 12- to 15-year-olds active on social media use WhatsApp, according to a 2017 report by the media regulator Ofcom.
That made it the fifth most popular social network with the age group after Facebook, Snapchat, Instagram and YouTube.