How do I downgrade to Subversion 1.6?
What you could try is changing all your entries in /etc/apt/sources.list to precise, like this
deb http://extras.ubuntu.com/ubuntu precise main
deb http://us.archive.ubuntu.com/ubuntu/ precise main universe restricted multiverse
then run:
sudo apt-get remove subversion
sudo apt-get update
sudo apt-get install subversion
If the install of subversion 1.6 works out for you, then you'll want to revert your sources.list, and to lock subversion at 1.6 you run echo subversion hold | sudo dpkg --set-selections
This type of installation is not highly recommended, but sometimes it's the easiest option. If it runs into all kinds of crazy conflicts, then you're other best option is to just switch back to Ubuntu 12.04.
If you have Synaptic Package Manager installed, you can force-downgrade Subversion to an older release. Just look up Subversion in Synaptic, right-click Properties, go to the Version tab and check what versions are available to you.
If you're lucky enough, you will find both an 1.7 version (1.7.5 in my case) and an 1.6 version (1.6.17). Close the Properties window, select Subversion from the list, go to the Package -> Force Version menu item and select the desired version.
If everything worked out fine you'll only need to worry about Ubuntu updating your software to the most recent release. In order to stick to the 1.6 version, you can lock this update: Package -> Lock version. And voila, you're back to good old 1.6 :)
I have successfully downgraded to 1.6 by manually downloading the 12.04 svn and dependency packages from http://packages.ubuntu.com. I first uninstalled version 1.7. Then, I installed the Ubuntu 12.04 packages in the listed order.
libdb4.8_4.8.30-11ubuntu1_amd64.deb
libsvn1_1.6.17dfsg-3ubuntu3_amd64.deb
subversion_1.6.17dfsg-3ubuntu3_amd64.deb
subversion-tools_1.6.17dfsg-3ubuntu3_all.deb
The other solutions did not work for me.