Checking for Updates
Mike's Sprite Editor is still in beta, meaning that it is neither finished nor completely stable. Features are still being built, and bugs are found regularly, so updates are fairly common. If you want to be alerted when new updates are available, there are two ways to do so.
You could always subscribe to the project on Sourceforge. This option is not going to be everyone's cup of tea, so I've prepared another, easier method.
As of version 0.11, there's an option in the Help menu to check for updates. When selected, the editor will go online and request the editor's latest version number. You'll know in a moment if a newer version is available, and if so, a button will appear that will take you to Sourceforge's download page.
The Update Window (while checking)