Microsoft is ending their support for Internet Explorer 8, 9, and 10 in the middle of January 2016, only providing technical support and updates to IE 11 and Edge. So if you are using one of the older versions of the browser, you could become infected by Malware/Spyware more easily than if you are running one of the newer editions. They are free, so there’s no reason to not upgrade unless your operating system will not support them. Then you really need to consider upgrade your whole system. Windows 7, 7.1 and 10 will all run Internet Explorer 11. Find the downloads on the TechNet Microsoft Internet Explorer page.
If you open an older version of the web browser this week you will receive a message telling you to upgrade. There will also be one last patch distributed to update all virus protection prior to ending support.