The version of the interface that you are using should match the version of the interface that the collector links to.
If they do not match, you will be presented with the following warning message:

Click OK to continue.

To find out which version of the interface is running, click on the About box:

If you have already defined a Collector within Hach WIMS client that links to the appropriate version, you can select it from the Configuration / Collector Configuration screen:

If there is not a collector in the list that links to the appropriate version, you will need to create a new collector or modify an existing one in Hach WIMS Client.

To modify an existing collector or add a new one, go to your Hach WIMS Client and click on System Setup / System Tables / Enter System / Server-Side Interface Setup from the main menu:

To add a new collector, click on New. To modify an existing one, click on Edit next to the appropriate collector:

If you are editing an existing collector, click on the blank button near the top right hand corner to open up the Definition Browser Screen:

In the Definition Browser screen, click on the appropriate version and click 'Finish':

If you don't see the appropriate version listed, then you need to update your g2_server_lu file. You can do that within the interface by clicking Utilities / Upload definition file to Hach WIMS from the main menu: