As Debra Tate also mentioned to People, the release date for the film was also moved.
Sony has since moved the release date up two weeks to July 26, 2019.
Once Upon a Time in Hollywood was originally slated to release on August 9, 2019, fifty years to the day from the murder of actress Sharon Tate and four others in 1969.
This is good to hear because you don’t want a film that depicts a real life tragedy to be insensitive or hurtful to those still suffering the effects of that tragedy.