December 18th, 2014, 15:49
If you mean two separate installs, yes.
Start by copying your 1.40 install and installing 1.50 into it.
You will also need copies of your 1.40 desktop icons, and reset them in Properties for each icon to the new install for 1.50.
The batch files within the new ETO main game folder will have to be edited to reflect the new location.