Facebook today released a new version its iOS app to include a way for users to change their cover photo and a number of updates related to group messaging. A subtle but significant change not mentioned in the app’s release notes is that the option to hide a post or ad and mark it as spam is now a different color, making it much harder to see.

The images below show what the button looks like on organic posts and suggested posts. Users can still hide a story by clicking the V shape in the top corner, but they might not be able to see the option from their mobile feed. The icon is practically invisible on ads, which could reduce the amount of negative feedback they receive. This could lead Facebook to believe that users are more pleased with their feed than they actually are.

Compare the color of the icon above with how it looked on ads and organic stories in the previous version of Facebook for iOS.

At the same time that Facebook is testing a less noticeable icon on iOS, it has made the option to hide News Feed ads even more prominent in the latest version of the desktop feed.

Other changes in today’s iOS release, include the ability for users to change their Timeline cover photo and group message features that were brought to the standalone Messenger app recently. A new prompt encourages users to name their conversations with multiple friends — a feature that was previously buried. The app also supports search for existing group conversations, whereas before users could only search for friends and other users to message.