New Bitcoin Core
release 0.11.1 obviates the problem by mandating LowS.
This is a very good thing, nevertheless, I'd consider high S -> low S mutation as complementary measure, because a) there are nodes out there, which don't use the new policy, b) and miners, and c) wallet implementations.
Note that the policy rejects high S, which may result in legit transactions getting dropped, which is probably not a favorable outcome.
I am kind of surprised, very few transactions are LowS malleated. Nodes to which I connect always ask me to send the payload...
I thought I was not alone oO
Or maybe the HighS already reached all the other node so the LowS version is always ignored...
I'm running the "seed" branch, and I see many log entries indicating high S -> low S mutations from my node.