1. ​​Adddominik's repository: sudo apt-add-repository ppa:dominik-stadler/subversion-1.7​​
  2. ​​Updateapt: sudo apt-get update​​
  3. ​​Installsubversion 1.7: sudo apt-get install subversion​​

http://blog.jedf.com/2012/06/installing-subversion-17-on-ubuntu-1204.html