As Adhiyan mentioned, you simply have to change the editing mode of the delivery content to DCE from the delivery's properties (or from the delivery template's properties), as explained in the introduction here: Delivering with the DCE
I think the version is not the problem here. Unless your console version is far different from your server version (you can see both under Help > About and they should be the same or close, otherwise it would certainly lead to some unexpected problems).
Have you seen this page? Email channel - The "Open" button mentioned should be available.
There are currently 3 supported versions of Adobe Campaign:
Adobe Campaign v6.1 (console version)
Adobe Campaign v7 (latest version of the console version)
Adobe Campaign Standard (web version)
You can consider v6/v7 as the same product and Adobe Campaign Standard a different product (as it is based on a different infrastructure).
For each version, regular updates are released. From your version, you can find your build number from the Help > About menu. There you can see the version and build number of both console and applicative server.
For 6.1.1 you can consult the release notes here, where you'll be able to see all new builds and features added for each new release. And if you're saying that your version is from 12/18/2015, it is probably outdated. The ways to have it updated depends on whether you are hosted (in this case you can ask Adobe to do it for you by opening a ticket) or on-premise (in this case you can ask your IT department or person responsible for your Adobe Campaign installation).
Whether you can see an option or not ultimately depends on 2 things:
Build number (recent builds have obviously more features)
Packages installed on your instance - Campaign has many options (depending on your contract) that can be activated. These options can lead to new buttons/features visible in the interface.