In order to lock a package to a specific version and refrain it from being upgraded do:
sudo -s
echo PACKAGE_NAME hold | dpkg --set-selections
To verify the settings for a package to:
sudo -s
dpkg --get-selections PACKAGE_NAME
To re-enable a package to be upgraded do:
sudo -s
echo PACKAGE_NAME install | dpkg --set-selections
More info can be found here:
https://help.ubuntu.com/community/PinningHowto
