is a 15% drop what others are seeing on other platforms?
Yes, that's about right.
Just updated my xeon servers running Ubuntu 16.04 and both are getting the same hashrate as before:
Dual e5620 - "hashespersec" : 231110,
Dual x5650 - "hashespersec" : 392413,
Both showing new version:
"version" : 91601,
"protocolversion" : 70020,
I'm hoping it doesn't matter, but I left the hidden directory in place with the old .conf file, etc.