Apple today announced in an updated support document that the Back to My Mac service is being eliminated from all versions of macOS on July 1, 2019.
Apple previously warned that Back to My Mac support would be eliminated in macOS Mojave, but the updated wording seems to suggest the feature will be removed from all versions of macOS rather than just macOS Mojave.
As of July 1, 2019, Back to My Mac service is not available in any other version of macOS. You can use these alternatives for file access, screen sharing, and remote desktop access.
macOS Mojave has not had the Back to My Mac feature since the first developer beta launched, and Apple confirmed plans to end support for the feature in August 2018.
Read more at MacRumors.com