There are several ways to find this out:

OPTION 1:

1. Go to Options (Wrench) on your main screen with all the icons
2. Go to About at the top
3. You will see the information below.
4. Please let us know the numbers in the first 3 lines.  For example: 8130/4.5.0.169

OPTION 2:

1. Compose a new email
2. In the body of the email type "myver" like below

3.  Make sure you hit the space bar to complete and you will see the information below

4. Write this full information down.