Twitter over the weekend dropped the iconic bird logo and replaced it with the letter ‘X’ to make a big splash in the evolving company following Elon Musk’s takeover.

The app in the app stores for both Apple and Android has changed from Twitter to X early Sunday morning.

It is still unclear whether the change to the logo will attract more users to the struggling social media brand but on Saturday, there was an investigation into a giant “X” sign that was installed Friday on top of the San Francisco building formerly known as Twitter headquarters.

City officials say replacing letters or symbols on buildings or erecting a sign on top of one, requires a permit for design and safety reasons.

Nonetheless, X falls in line with Musk’s other X-named brands, SpaceX and Tesla’s Model X. Also, it is the name of his young son, whom he calls “X.”

Musk’s goal for X is to turn it into an “everything” app — for video, photos, messaging, payments, and other services.