If you installed from testing then you can just downgrade the appropriate packages. The arch wiki has an entire page dedicated to the process, warnings, and how-tos of downgrading packages: https://wiki.archlinux.org/index.php...ading_Packages
Keep in mind...
Consider the dependencies of each program. The required libraries often change with each version, and the functionality of associated files may be completely different from previous ones. The solution will require changing these to earlier versions as well.
Now, all that assumes you installed actual arch packages... if you built and installed by hand then things get complicated, and again...ask the Arch forums.