That may seen odd, but it could happen in a open-source world: multiple parties releasing different versions of the same piece of software and calling it the same.
The result is the main RPM everyone uses will probably stay at version 4.x forever.
[0]: http://rpm5.org/
"Initially, nobody registered it, but on August 15, 1994, [...] filed for the trademark Linux, and then demanded royalties from Linux distributors. In 1996, Torvalds and some affected organizations sued him to have the trademark assigned to Torvalds, and, in 1997, the case was settled." https://en.wikipedia.org/wiki/Linux#Copyright,_trademark_and...