We just upgraded to version 7.1.4 last week. This was our first upgrade as we went from version 5.0.6 to 7.1.4.
In the release notes, it suggests running the following:

"MySQL table upgrade is required after upgrading to ZCS 7.0 or later. MySQL table upgrades are not automatically run during the upgrade to 7.0 based on time that it takes this process to run. There is no known performance impact when running in production without doing this MySQL table upgrade. Customers can avoid these errors in the zmdbintegrityreport output by executing /opt/zimbra/libexec/scripts/migrate20100913-Mysql51.pl.
(Bug 24329, 50557)"

We have not done this step. Is it necessary? Will I run into problems if I try to do another upgrade or install a patch?

Any advice is appreciated.