You can see the version of Creately Desktop you have installed by looking next to the Creately logo in the top left-hand corner of the screen when you have the diagram dashboard open. The below image shows an example of what this looks like:
You can open the preference tab on the desktop app to ensure the version as shown in the screenshot below,
When you're on the editor/canvas area, you can simply press Ctrl+F7 key on Windows or Fn+Cmd+F7 on Mac to bring up debug information to access the desktop app version. Here's how it'll look like (Product Version),
You should ensure you always have the latest version to make sure you don't encounter any known issues and always have the latest and greatest features.