Hi, I have used ISSU for 6509 VSS to upgrade the IOS From s72033-adventerprise_wan-vz.122-33.SXI5.bin,12 to s72033-adventerprisek9_wan-vz.122-33.SXI5.bin,12; version I have referred below link for ISSUhttp://www.cisco.com/en/US/docs/switches/lan/cata...