Four Mysterious xCloud Program Codenames Surface in Microsoft’s API Hinting at New Game Pass Tiers

Microsoft could be planning another major update to Xbox Game Pass. First spotted by Gamerant, a Bluesky user named Redphx recently uncovered four unknown xCloud program codenames, Callisto, Dia, Europa, and Ferdinand.

Apparently, the user found these details while digging through Microsoft’s publicly accessible API. To catch you up, these names don’t match any of the current xCloud offerings, and they may point to a fresh wave of Game Pass tiers or features.

As you may know, Microsoft runs three clear xCloud programs: Xbox Game Pass Ultimate, a bring-your-own-game option (BYOG), and a Fortnite-only free tier. No doubt, the recntly discovered xCloud program names are vague. But, it seems that they’re tied to xCloud in some capacity.

Microsoft last revamped its Game Pass lineup in late 2024. That change introduced Game Pass Standard and replaced Xbox Live Gold with Core. Since then, fans have speculated about more cloud-specific tiers. This leak gives that idea new weight.

Intrestingly, at least a dozen games in the API are already flagged under one or more of these four names. Titles like Assassin’s Creed Origins, Hellblade 2, Genshin Impact, and Undertale all show links to Callisto, Dia, Europa, and Ferdinand. Even GTA V appears, though only the Xbox One version.

For now, Microsoft hasn’t commented on the leak, and the names don’t appear in public-facing plans. But the presence of recognizable game titles tied to these programs adds credibility.