By "backup server" I take it that you do not mean "a server for running back ups" but something more like "a hot (/warm) swappable server, to fulfill the same tasks as the primary server".
Nevertheless you are using quite an antique Red Hat release
...absolutely... Fortunately, this presents an opportunity. Roughly
- Get new hardware
- Install recent software
- Configure everything and test
- Bring old server up to new software standard and use as hot swap server
Note that you should not underestimate the process of going up to the new software from your current ancient version. It might, if you are lucky, be trivial, but you still have to do the testing, because you can't rely on that. After all, its not just a small incremental upgrade that you are taking.