Meta is switching off the ability for under-18s to receive messages on Instagram and Messenger from anyone they do not follow or are not connected to, by default, as part of a safety update. The social media giant said the change is part of its ongoing work to provide “age-appropriate experiences for teens” across its apps. The change extends an existing Meta policy which does not allow adults to message teenagers who do not follow them, meaning no-one on Instagram or Facebook Messenger will now be able to direct message a teenager who does not follow them. “Under this new default setting, tee…