Contribution to openhab-addon "Stiebel Eltron ISG" - how?

I have the Stiebel Eltron heatpump WPF07 installed and I needed more
channels. So I have enhanced the openhab-addon “Stiebel Eltron ISG”
quite a bit. I want now to share my changes with the community.
As there a rather many changes to the code making the addon incompatible
with the existing version (renamed existing channel IDs for better matching
the documentation), I would like to know, if I should create a new addon
“Stiebel Eltron ISG V2” or if I shall create pull request on existing addon.

Thanks for helping me in this.