Ipod help

i have an old (very old) ipod touch with ios 4.2.1 installed and latest wd app wont work with this can install an older verison onto my ipod and where would i get it from?

many thanks in advance

You must have the 2nd gen Touch – I have the 3rd gen iPod touch and it supports all the apps (iOS 5.1.1)

But if you don’t see the app available in the app store, then no older version exists (or WD doesn’t allow it), since Apple now allows older devices to download older versions of apps directly through the app store.

http://www.infoq.com/news/2013/09/previous-version-ios-apps/