The Gemini PDA is a throwback to the days when people thought they needed a physical keyboard to manage their portable devices. Sailfish OS is an Android alternative based in part on Nokia's MeeGo project and created for the Jolla phone that works on the Gemini as well as a number of Sony's Xperia handsets. Now the Gemini PDA will feature Sailfish officially; it will also be available to download (as Sailfish X) in late 2018.
Sailfish X will feature OTA updates, access to the Jolla Store, end-user support and (aimed at Gemini users) full landscape interface support. It will also include Android app support, encrypted user data, and a redesigned email app. If you're looking to get in on the Sailfish action right now, there's a community-supported version based on the 2.0 iteration called Sailfish for Gemini Community Edition that's free to download.