RPM 4.15 is due out this year as the latest RPM4 update and Fedora 31 is planning to make prompt use of RPM 4.15 given its new/improved features.

RPM 4.15 is expected to provide faster build performance, a dynamic build dependency generator, experimental chroot operations for non-root users, improved ARM detection, and a whole lot of fixes.

More details on the RPM 4.15 features/changes are tentatively outlined on RPM.org.

There is now a change proposal awaiting evaluation by FESCo for approving the switch of Fedora 31 to make use of RPM 4.15. Fedora 31 is due to be released this November.