There is in the sense of beta releases that contain previous builds, but whenever you sync the version automatically gets updated to the latest one. So, if you never sync again you can run a lower version, not very practical ;-).
I have not seen anybody that managed to go back a version succesfully, so the answer is 'No you cannot' unfortunately. Having said that most battery issues are related to the software misjudging the amount of energy, some solutions are seen on the forum (like soft/hard resets etc) which for some users seem to work.
