Unfortunately, you cannot downgrade the Internet Explorer 11 browser to its previous version on the Surface Pro 2 running Windows 8.1 operating system. This is because the Windows 8.1 Operating System comes with Internet Explorer 11 browser preinstalled with it.
However, you may try using the Internet Explorer 11 browser in the previous browser version mode using the F12 Developers Tool and check if that helps.
To change the browser mode, you may follow these steps:
1. Open the desktop version of Internet Explorer 11.
2. Press the F12 key on the keyboard to open the F12 Developers Tool for the Internet Explorer 11 browser.
3. Press "CTRL" + "8" to open the "Emulation" section of this tool.
4. From the "User Agent string" drop down menu, select the browser mode which is compatible with your work platform and check if that helps.
5. You may close the F12 Developers Tool. You may re-enable this mode whenever needed by following the same steps.