This isn’t an April Fool’s joke, although the timing is perfect. Ryan Reynolds used his Twitter account to officially announce the release date for the Deadpool Blu-Ray as May 10th. The April Fool’s part of the announcement is of course the VHS and LaserDisc releases (although a LD release would be cool!).
In addition to Blu-Ray, Deadpool will be released on UHD 4K Blu-Ray. It’s not known yet if that will also be on May 10th, but it’s likely to be the case as Fox has been pretty good with their 4K releases so far. X-Men: Days of Future Past is already out in 4K, so if you have one of the new players you can have the two best X-Men movies on the format when Deadpool releases in a couple of months.