SerializationException error

I have worked with Manager for some time. I then tried the Cloud trail version and I liked it. The problem I am having now is that I can’t open the Desktop version. I get the following error. What to do now?

You are probably using some very old version of Manager on your desktop.

Upgrade to the latest version from http://www.manager.io

Thank you Lubos. Strange enough, I downloaded he same version last week and it did not work. This time around it did work. Thanks again.
Randy