Anna is back and no more backseat action! Want to know more?! Read it all here.
'Anna returns and wants to kill Sam, so he doesn’t say yes to Lucifer. She travels back in time to kill Mary and John Winchester, so Dean and Sam go back in time to try and stop her.' Source Supernatural.TV
As per my previous post, there is an up-coming episode called Back to the Future II, may be Anna will appear on that episode?! Stay tuned!