Karba was working in the Forest support since some weeks ago. We didn't want to announce it, until we are sure there was not problems with the implementation. We just received his confirmation that everything is working fine.
He used a modified Forest version, which includes a new custom interface. So, the Octane support will be included in the upcoming Forest 4, that we are developing now. This release also will include support for Arion Render, Thea Render and other engines that i cannot announce yet.
I think the first beta should be ready within three of four weeks. As always, the beta will be available for all Forest Pro customers with active subscriptions.
About Octane, i have not tested it yet, so please be patient. As far as i know, it includes only instancing support, not Forest Color.