Apple does not force iPhone and iPod updates.
As far as I know no one "forces" them. Everything released up to the point the firmware update is released will still work. But with Apple, there are apps that require the latest updates, thereby "forcing" you to update if you want to use those apps.
"'Tis true, 'tis pity, and pity 'tis 'tis true." -- Poloniouius, in Willie the Shake's _Hamlet, Prince of Darkness_