https://bugzilla.redhat.com/show_bug.cgi?id=1594044
--- Comment #2 from Mikolaj Izdebski mizdebsk@redhat.com --- Maven 3.5.4 is available for Fedora 28 as a module. You can install it with:
dnf install fedora-repos-modular dnf module install maven
At this point there are no plans to update non-modular maven packages in Fedora 28.