Out of date test strips over or under read

To be honest there is no way of really knowing, they could be accurate, they could show low, they could show high, or they may just not work

I'd buy a new pot of teststrips. I wouldn't expect the changes to be predictable.

Sorry I can't help, as I have never had any out of date strips to use.

My original meter over 7 years ago was a Nano which I used for about a year. I recently resurrected it after my current Contour Next mysteriously went walk about. and I found some well expired Accu Chek strips. I used these as a last resort while in the process of replacing the Contour, then also tried both side by side for a few days out of curiosity as the Nano was giving me very similar figures to those from my Contour . To say the least I was more than slightly gobsmacked, so it may be worth a try to see how using your old strips might compare with your recent readings, but I wouldn't necessarily rely on them!