The Untitled Cloverfield Movie, the film with still no official title announced, formely known as God Particle, will once again have its release date delayed.

The Untitled Cloverfield Movie, which for a while was going under the name God Particle, has had its release date pushed yet again. The film, set to follow the surprise semi-sequel 10 Cloverfield Lane, was initially announced for a February 24, 2017, release date. The production reportedly went through some reshoots supervised by producer JJ Abrams, and that date moved to October 17, 2017. Then the date moved yet again, to February 2, 2018. With February fast approaching, it seemed slightly strange that there had been no real marketing for the film released yet, and now we know why: it’s been pushed back one more time.

Now, Paramount has confirmed to us that the Untitled Cloverfield Movie will find its way to theaters on April 20, 2018.

Source

The same article also states that the script was written before 10 Cloverfield Lane and was later rewrite to be a part of the franchise.