Days ahead of Meta CEO Mark Zuckerberg’s appearance before Congress, the company has announced new features designed to better protect children using its Instagram and Facebook platforms from receiving unwanted sexual advances and encountering inappropriate content.

Zuckerberg, along with the CEOs of X (formerly known as Twitter), TikTok, Snap and Discord, have been subpoenaed to discuss online child sexual exploitation before the Senate Judiciary Committee on January 31 in the wake of whistleblower testimony and increasing public outcry about how the platforms potentially endanger children.

A Meta blog post on Thursday said it will now default to blocking children from receiving messages from anyone they don’t follow or aren’t connected to, including other teens. The blog post also said teens with supervised accounts will need parental permission to alter the setting.

Meta said the default setting will apply to all children under the age of 16 or, in some countries, 18.

“Under this new default setting, teens can only be messaged or added to group chats by people they already follow or are connected to, helping teens and their parents feel even more confident that they won’t hear from people they don’t know in their DMs,” the blog post said.

The company noted that it already blocks adults older than 19 from messaging teens who don’t follow them and blocks users from sending more than one text-only message to people who don’t follow them.

Earlier this month Meta announced another raft of changes in the wake of an October announcement that a bipartisan group of 42 state attorneys general are suing them because their product allegedly harms children. Shortly thereafter, Meta said it would default child and teenage users to its strictest content settings.

Thursday’s blog post also said the company is planning a new feature “designed to help protect teens from seeing unwanted and potentially inappropriate images in their messages from people they’re already connected to, and to discourage them from sending these types of images themselves.”

Meta did not offer further details, saying it will reveal more about the feature, which also will be used in encrypted chats, later this year.