Unable to update after iTunes ID has been changed
Apps, books, tunes &amp; even the iOS itself belong to the ID that purchased them.  

When you say you have 'changed your account' I'm guessing that rather than simply changing the primary email address on your old ID, you've set up a brand new one.
This will now leave you in the position that each time you need to update the OS or any app, you will need to sign in with the old ID again.

It is not possible to transfer any apps, books or tunes from one account to another so unless you completely erase the device &amp; start afresh with the new ID, repurchasing previous software, then you are stuck with this double sign-in.

The additional problem with having set up a new Apple ID with your new email address is that you can now no longer change your primary address on your old ID to that address.

This is the method to change a primary email address - for future reference.
You may be able to call Apple &amp; see if anything can be done now, but I'm not sure it can.

Change your Apple ID

Follow these steps to change the email address that you use as your Apple ID.


Sign out of iCloud, the iTunes &amp; App store, FaceTime, Find My Friends, Find My iPhone, and iMessage on each device that uses your Apple ID.
Sign in to your Apple ID account page.
In the Account section, click Edit > Change Email Address.
Enter the email address you want to use as your Apple ID. A verification code will be sent to your new email address.
Enter the verification code from the email into the fields provided and start using your updated Apple ID. Didn't get the email?


You can change your Apple ID to any other email address you control, as long as it's not already in use as an Apple ID. If your email address ends with @icloud.com, @me.com, or @mac.com, you can't change your Apple ID and you won't see Change Email Address on your account page.