Preview
Some features of a main version can be available in the version before as a preview. They are announced and flagged as such. These features like to say:
"Dear user, please have a look what will be coming in the next main version. We have created a new feature, what do you think about it?"
Such features are in the stadium of development but already work in a presentable manner. There will be changes and amendments made and we'd love to hear our user's opinion on the feature. Ideas for improvement or pointing at errors are welcome. As soon as the new main version will be released the preview in the before version may end. If you don't like to juggle with a preview, please ignore it from the beginning.
Looking forward to a lively discussion.