There have been many questions regarding Microsoft Internet Explorer 8 and Clarity.
Some users want to know with which versions of Clarity is IE 8 compatible and others want to know how it was decided which version of Clarity would be the one to become compatible with IE 8, especially given IE 8 was released year end, 2009.
Clarity PPM is compatible with IE 8 beginning Clarity 12.1.0.
There are two reasons this particular version of Clarity was chosen as the most appropriate version of Clarity for IE 8 compatibility;
Note: Some users seem to be able to work 12.0.xxx with IE 8 however it is not supported and can cause strange behavior in versions of Clarity prior to 12.1.xx. For instance tabs can show up blank or parts of the page you are viewing can appear to be missing.
Reference the current Clarity Product Architecture Stack (PAS) documentation for your implementation of Clarity.