Upgrading to new iPad Pro from iPad retina running release 10 windows iTunes backup.

What do you mean my software is too old. Release 10 on iPad that is backed up to windows 10 to new iPad which Is Os 11. Is that why my messages are missing, most of my mail, and the majority of my apps. I do not wish to upgrade my old retina iPad to 11, as I need to run apps that have not been converted to 64 bit on it. Geeeeeeeeze guys