What do you mean by old version of apache.
Apache has two different trees:
- Apache 1.3x
- Apache 2.0x
cPanel currently supports Apache 1.3, 1.3.34 is the latest version in the tree. I think support for 2.0x is being worked on, however 1.3.34 is not out of date and at present there is no real advantage in upgrading, if you can that is. Since it is not cPanel supported, you would have to compile everything outside it.