Fedora 29 confirmed that the package manager Yum will not be deprecated
Since DNF is quite mature as the next generation of package managers, there are plans to deprecate Yum in Fedora, but this will not happen at least until Fedora 30.
Fedora 29 will not deprecate Yum, because if this will cause considerable disruptive changes during this development cycle, there are still some critical infrastructure components that depend on Yum, such as Koji, Pungi, etc.
Therefore, at the recent Fedora Engineering and Steering Committee (FESCo) meeting, Fedora 29’s plan to abandon Yum was rejected. However, this work is likely to be revisited when Fedora 30 is released next year.