Fedora 28 will be EOL on Tuesday, May 28th, 2019. On this day we are going to close all of the Fedora 28 bugs which remain open [1].
You have a few weeks remaining to submit updates, if you have any, before the Fedora 28 release becomes unsupported.
[1] https://fedoraproject.org/wiki/Releases/30/HouseKeeping#Fedora_28_EOL_Closur...