New install has a warning I've never seen

I am moving an existing Percona instance to a new server running RHEL 7.2. The existing server is Centos 6.5 and there are no warning there. The install ran without any problems.

I used the yum repo install described here:
I used the Webtatic repo to install PHP 5.6 as described here:

So the problem is fairly minor, but one I don’t like to see on a production server. When ever a db connection is made I get this warning:

I do not get the warning when using PDO.

I never like turning off warnings and I don’t like seeing them, so I’d like to fix this. Any ideas?

Hi wesmat, don’t know nothing about Webtatic php repo, I’d upgrade or rebuild php from command line to run with the mysql 5.7 version

I think I’ll try a different repo. Redhat has one called RHSCL that states it supports PHP 5.6. This is probably a better choice anyway.