I've read that IE won't be supported on Windows 10 anymore. Official page: Microsoft
We have a Java applet application what we can run in Edge, but for certain types of Operating Systems (Windows 8.1), there is only Internet Explorer installed on the machines.
What is not clear for me that will Win 8.1 still have support for IE 11?
According to the documents yes, but I want to know for sure.
Internet Explorer 11 desktop application will still be supported on the following OS:
So yes, Win 8.1 still have support for IE 11. For more information about IE 11 retirement, you can refer to this doc.