* One of the characters sees a photograph, and reflects that its quality is low enough to suggest that it was taken after the Change. A camera in 1998 would still have used chemical reactions to form images; cameras now are virtually all electronic and would have stopped working.
* One of the characters reflects that a lot of people have had trouble adjusting to not having music constantly with them, since Walkmans don't work. The first iPod was released three years after the Change; The Protector's War was published in 2005, but Stirling was careful to use a period trade name (apparently "Walkman" is now being used for digital devices, but of course it's not the industry leader).
This is kind of like reading a Heinlein novel where the engineers use slide rules. But it's a bit startling that it's happened already to a series that's still coming out.