Hi Tim,
I think its likely you will encounter some issues (due to it not being qualified in IE11), but without actually running 7.5.4 in IE11 its hard to tell what these might be.
As the system is uncustomized, is there any reason why you can't upgrade to the latest version?
For your reference, the latest version of the Compatibility Guide can be found below on our Knowledgebase (though the IE11/7.5.4 box remains greyed out).
https://qgate-cdn.s3.amazonaws.com/assets/infor%20crm/marketing/InforCRM-Compatibility-Guide.pdf
Regards,
Lee |