I can't update - not yet on ios9 - but the mobile ticket stored still seems to be accessible.
On these reports, I don't think I'll bother yet if/when I upgrade to ios9. Shame as I was collecting Nectar very nicely booking most tickets through it. But why deactivate the old version? Madness, there are some iphones not able to upgrade to ios9 still in use
The met office also recently did that with their app, but they didn't give any prior warning at all, the old one just stopped working with no indication it had been replaced.
Not sure if this is becoming a thing amongst app developers?