Nextbit has been acquired by Razer, promises Robin patches through February 2018
So it's not being shutdown like what Fitbit did with Pebble.
According the the announcement on Nextbit's site, the Robin and all accessories are no longer being offered for sale. However, Nextbit will honor the warranty on all products for 6 months from today. Security patches will also continue rolling out through Febriary 2018. The company will continue operating as an independent company within Razer, working on "unique mobile design and experiences." It's not clear if that means smartphones, but I'm not sure why else Razer would buy a smartphone maker. Some quotes given to TechCrunch seem to indicate phones are still the plan.