Yes, QV v12.10 SR1 does support IE Plugin with IE 11. Please note that IE Plugin is not supported with the Edge browser. https://help.qlik.com/en-US/qlikview/12.1/Content/System-requirements.htm.
Yes, best practices dictate that you'll want to run the same version of QlikView Desktop as that of the QlikView Server. That way, you'll ensure that any/all development of QVWs is done on the same version.
Hope this helps.