There are two aspects to this. One is that when equipment gets delivered, a high-technology new kit, there are often small, or sometimes not so small, defects in it that get fixed by engineering processes either in government or in the company. That's quite normal. You don't expect a big, complicated piece of kit to work absolutely perfectly from day one. We do our best, but it happens. Sometimes, if the shortcomings are really serious, then there's a big row, but that's relatively uncommon.
The other part of it, though, is that in this day and age you should know that certainly platforms that you acquire are going to need fairly regular, constant updates on them, so this term “open system” is becoming commonplace. It means that you can make improvements without taking the whole machine apart, that it's a relatively simple process to do. With software, that's often relatively easy. Sometimes it's more difficult with things like integrating new weapons onto a platform and so on.
There is fixing the immediate faults, but also recognizing that a thing that's going to be in service even for a decade is going to need in-service improvements and that you want some assurance that it is an open system.
I could give you some examples, but six minutes doesn't allow that. If you write in, I will send you some examples.