Java – Ubuntu: downgrading Subversion from 1.6 to 1.5

You'll need to prepend the /opt/subversion version in the shell's path to have the environment prefer the new version.

The software's README states:

Installation Notes

<snip>

Once installed, you will need to prepend /opt/subversion/bin to your PATH environment variable.
This can be done a multitude of ways but an easy one is to add the following to the end of /etc/profile or ~/.profile:

export PATH=/opt/subversion/bin:$PATH

Back up your data.

List the transaction with yum history and undo it with yum history undo

How to use yum history to roll back an update in Red Hat Enterprise Linux 6 , 7?