Hi,
TestComplete 9 and TestComplete 10 licenses can be activated on one computer. However, having both licenses activated is available only during the period when moving your test projects. Once the projects are moved, and you make sure that they successfully work, you need to deactivate the old license.
In TestComplete 10.4, we have stopped supporting several features. Please make sure that you don't use them before moving to this product version. Refer to the
Discontinued Support section of the
"Features Added to TestComplete 10.40" article.