Significant changes in this release to the general appearance of all of the charts - changes to the background grid (for charts that use one), the axes and the colors in an effort to modernise the appearance of the charts. If you don't set any of the changed properties, then your charts may change in appearance slightly. If this is the case, though, you can just change them back by setting them in your charts' configuration. Also, the default colors for all (or most) of the charts have been changed to a semi-opaque set of 33 colors. You can see all of the new colors here: https://www.rgraph.net/canvas/default-colors.html
You can see the full changelog here: https://www.rgraph.net/changelog.html
And you can download RGraph here: https://www.rgraph.net/download.html