Include additional data into iPhone backup files I have two iPhone backups available, one recent and one older.  

Is it possible to inject/include/simply add content from my recent backup to the older one?  

So that when the iPhone is restored from the older backup, the content from the recent one would be restored as well.

I have some apps installed that don't give me any option to export my content but I have to restore to the earlier backup missing the app or its content.
You can using various third party backup and restore software. I like iMazing and know there are a few others out there.