Can't sign into app because it has my old email. How do I fix this?

[pgygax]

When I try to sign in to iTunes to update an app, it still has my old email, the password to which I don’t remember. Is there a way to change the iTunes setting on my phone? Or do I have to erase everything?

 

[J. A.]

If you don't remember the password for the old Apple ID, you won't be able to update the app.

If the email address still exists, use this site to reset the password of the old Apple ID:
Recover Your Apple ID - Apple
It should be possible to update the app afterwards.

Apps are connected to the Apple ID with which they were downloaded/purchased, and can't be transferred to another ID.

If you wish to use the app, and keep it up to date, but you don't remember the password, or can't change it, you'll have to remove it from your iPhone and purchase it with your current Apple ID.

 

[pgygax]

If you don't remember the password for the old Apple ID, you won't be able to update the app.

If the email address still exists, use this site to reset the password of the old Apple ID:
Recover Your Apple ID - Apple
It should be possible to update the app afterwards.

Apps are connected to the Apple ID with which they were downloaded/purchased, and can't be transferred to another ID.

If you wish to use the app, and keep it up to date, but you don't remember the password, or can't change it, you'll have to remove it from your iPhone and purchase it with your current Apple ID.

It's asking for my apple ID which I've changed and updated everywhere, I thought. This has happened before and someone told me to either reset all settings or erase all content and settings... whichever it was, it worked but I'm afraid to do the later in case I'm mis-remembering and I get it wrong.

 

[J. A.]

Reset all settings will not remove the Apple ID, so it's the latter that should help.