USA TODAY Network journalist Ilana Keller reported seeing a black logo after downloading a Facebook app update on her iPhone, as well as iOS update 17.6.1. Keller's phone was not in dark mode.

Facebook logo in black. Users shared screenshots and photos of the Facebook logo shown on their smartphones and devices and wondered about the reason behind this sudden change.

FACEBOOK users have been left confused after the app’s icon mysteriously changed overnight – and some suspect it might be a bug. People woke up to a different logo for the social networ… ...

It now is appearing as a black background with a blue "F," rather than the traditional white on blue, for some users. Dozens of users chimed in on a post titled "What's Wrong With The Facebook Logo?" ...

FACEBOOK users have been left confused after the app’s icon mysteriously changed overnight – and some suspect it might be a bug. People woke up to a different logo for the social networ… ...