Wickr Me and Wickr Pro both have the added security of leaving messages "locked" when you receive them. This means you can tap individual messages to see their contents, giving you more flexibility when you may not want others to see what you're opening.
This also allows you to choose when the Burn-on-Read timer starts for that message as well, making sure the timer doesn't start before you're ready.
Wickr Me users will have Automatically Unlock Messages disabled by default, while Wickr Pro users will have it enabled by default.
You can adjust the settings for either version in the Settings menu of your app.