SQLServer UnsupportedClassVersionError

You have to select a version of the JDBC driver that works with your JRE.

See this topic:

Also, running an old and unsupported Ignition version means you sometimes cannot upgrade associated components, like the DB you are using. The OP in this very old topic was using v7.5. You don't say what version you are using, but I suspect you should have started a new topic and provided more information. Thanks, Kevin