In an effort to improve and polish the user experience in Fluxonaut, we've decided to remove the historical chart functionality until it meets our standard of quality and ease of use.
The reason that we are still in beta is that we still have many features that we don't consider to be complete. Sometimes it's hard to cut a feature, but in this case, we felt it was necessary until it reaches our initial vision.
We apologize for the inconvenience. We are not committing to a deadline for reintroducing historical charts, so in the meantime, we advise you to check our Excel Add-in and export/link the data so you can visualize it.