Automated Unit Testing (AUT) is unavailable in 7.1.1 - 7.1.5.
Starting in 7.1.6, users can access AUT features from supported browser versions of IE.
IE8 limits expansion features
Valid from Pega Version 7.1.1
Internet Explorer 8 (IE8) does not support CSS media queries, which are used by re-expansion features in the Designer Studio. IE8 users with low screen resolution (800 x 600) and a small window size may find that the explorer area in the Designer Studio collapses but cannot re-expand.
As a work around, access the Designer Studio from another supported browser version and use the recommended, minimum screen resolution width of 1280 pixels.
All Pega product release notes can be found on their product pages.