The FDA usually expects the vendor to tell their clients any restrictions on software version and/or Equipment needed to make the system work according to specs. If there are no restrictions, then it is up to the client to validate their entire system works according to their requirements. I might call my vendor and make sure Vx of something works with Vy of something else as far as they know. It IS, after all, up to you as the user to make sure of this, but most of the vendors will help you with this verification if you ask. The FDA knows that not all parts of a system will be the same version, however the Vendor has to prove to the FDA that these versions work together as a system or that's when there might be restrictions placed on versions. Hope this helps. Robin