AES-256 is not the strongest currently available so can this be upgraded

This is the industry standard.

The strongest will not yet be fully compatible.

We always way up the pros and cons and keep a healthy balance.

A similar answer to your question can be found here

https://security.stackexchange.com/questions/184305/why-would-i-ever-use-aes-256-cbc-if-aes-256-gcm-is-more-secure