Hello Theodore Kimana,
You can solve this issue by reinstalling the Correct version selector. The Mendix Version Selector introduced in version 4.3.0 automatically selects the Modeler of the right version when you open a Mendix project file.
Hope this helps you.
Have you try to open the application directly with the right version of the Studio Pro instead from the mendix portal?
In the case the version are incorrect Mendix will tell you otherwise it would open normally.