How is the rules of upgrading, do I need to pay for a copy the RiOS image 5.5.5 if I allready have the 5.5.3? I don't currently have support with Rivebed.
You can upgrade directly to 5.5.5, or the last 5.5.x release which is 5.5.9b. It is only necessary to step upgrades when doing major upgrades, ie 5.5, 6.0, 6.1, 6.5, 7.0. There is a upgrade path tool at https://support.riverbed.com/software/appliance.htm to help with this.
