When I got Riverbed Stellhead 250H for Lab environment, first thing I checked was version of RiOS on device. It turns out that device was outdated and had RiOS 5.5.6, while current version is 7.0.3.

Next thing I did was jump on Riverbed Support web page to identify how to upgrade my test Riverbed, as there is always certain path of RiOS versions you have to go through to get to recent one.