IMAX has released their upcoming schedule, and it seems that Marvel might push the release date of Avengers 4 up a few weeks into April 2019. Fans are also advocating for a same-day global release, and Marvel may comply with this popular request. Marvel usually favors a staggered release date, such as putting the film out early in the UK, Western Europe, and other territories. According to Marvel, this is done in order to maximize box office turnouts, as there are different holidays in different countries. This can also help generate hype and word-of-mouth, and possibly manipulate the box office numbers in their favor. For Ant-Man and the Wasp, Marvel delayed the UK release due to the World Cup. In the case of Avengers: Infinity War, Marvel initially planned for a traditional staggered release, but it moved the release date up a few weeks to prevent spoilers and ensure a same-day global release.
Thanks to IMAX publishing their 2019 schedule, many now believe that the release date for Avengers 4 is moving up from the original May 3, 2019 date to a nebulous April 2019 date. The schedule lists release dates for 17 IMAX releases such as Glass, X-Men: Dark Phoenix, and Frozen 2. It confirms that Avengers 4 release date would be April 2019, matching an April release in the UK, France, and Germany. Nonetheless, the release date for other territories is still listed as May.
Although Marvel Studios has yet to release an official statement on pushing the release date forward, with the precedent set by the launch of Avengers: Infinity War, having a same-day global release would definitely be feasible.