Apple ID

You can change back to the old ID to update the app. You can try setting up Family Sharing between the IDs if you want to be able to share purchases made with the IDs.

Family Sharing.         

Family Sharing - Set up.       

Try this approach to solving your problem (per Eric Root initially). Sign out of the App and iTunes Stores; restart your device; and sign back in. Then check your apps needing updating to see if they are in your purchases history (https://support.apple.com/en-us/HT204088). If they aren't, you can delete them, and purchase/download under you current Apple ID if you want. If the apps are in your purchase history, contact Apple support. You can use these support options:

Get a call from Apple support to help solve your problem using this

link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362  Be patient. Sometimes Apple phone support is not available.

Apple Support Twitter https://twitter.com/AppleSupport  There may be a wait of an hour or so.

iTunes worldwide support via text or chat https://support.apple.com/choose-country-region/itunes After choosing your country, see the heading, Tell us how we can help.