I am Vinod. I will try my best to help you resolve this issue.
Are you being asked for a password ***** you try to update the apps? And do you still have access to your old email?
I am typing out the answer. Please give me a few minutes.
Then I am afraid there is no way to reset the password ***** that apple ID (associated with the old email). You may need to write to the itunes store to reset the password ***** it through their website
However, you will be able to create a new apple ID with the new email address. On your iphone, go to settings > itunes and app stores. Your old account would be listed there. Tap on it and click on "sign out". Now click on "sign in"and choose "create an apple ID".
Note: If you have any apps bought using the old apple ID, you will not be able to update those apps unless you have the password ***** that old ID.
no problem, you don't need to pay anything extra. It is a one time payment unless you have opted for any memberships.
I am sorry. I did not understand what app you mean?