There are a few methods for determining what version of SD Elements that you are currently running:
When logged into the SD Elements user interface, the current SDE version can be seen in the copyright statement at the bottom-right of each page.
When logged into SD Elements user interface, the current SDE version is represented by the most recent Release Notes available on the list.
1) Hover cursor over the Help icon at the top right of the screen
2) Click on Release Notes in the drop-down menu
3) Observe the most recent version displayed.
From a server shell account, there is a central 'sde' command which you can use to find the version. sde version