Upgrading the SA device in production to 7.3 R5 is a good option & mature enogh for MAG 6611. You can go through the
SA 7.3R5 release notes using the below URL and find information on issues fixed and outstanding issues that are not fixed.
Based on this revioew you shouldbe able to take a decision on upgrade considering your SA environment.
I see win7 & IE 10 support on 7.3R5 however if you have any specific requirement or fix needed for specific issue you can contact JTAC support by opening a case and work with them on the recommendations
Hope this address your query