Microsoft’s latest Xbox PC app update contains extensive references to the still-unannounced Mythic Achievement system, including its badge, unlock animation, dedicated sound and the underlying logic used to track completion. The newly discovered implementation goes well beyond the achievement filters that surfaced earlier this month and suggests Microsoft is preparing a system built around completing a game’s original achievement set rather than simply reaching a particular Gamerscore total.
The files were examined from Xbox PC app version 2610.1000.53.0 and include text for “Mythic achievement” and “Mythic achievement unlocked.” The app also contains separate locked and unlocked Mythic badges, multiple animation sheets and a dedicated MythicAchievementUnlocked sound file. Microsoft has not formally announced the feature or confirmed when it will become available.
More importantly, the app code reveals how Mythic appears to be structured. Achievements can now carry group identifiers, while individual games can include completion groups with a defined group type. The implementation specifically checks for a “BaseGame” group and ignores completion notifications tied to other group types, strongly indicating that Mythic is intended to track the original game separately from later add-on content.
The game page can show BaseGame completion as a numerical progress counter, with accessibility text describing how many “original achievements” have been unlocked. It also includes a “Required for Mythic achievement” filter, while achievements outside the relevant group can be labeled as “Add-on.” Once every achievement in the BaseGame group is complete, the interface can display a message stating that all original achievements have been completed.
That distinction is significant because it suggests DLC may not affect a player’s Mythic status. Xbox’s existing achievement system can become harder to interpret when games receive additional achievements after launch, since expansion content changes the overall completion picture. A dedicated BaseGame grouping would allow Microsoft to define exactly which achievements count toward Mythic while leaving DLC or other additional achievement sets outside the requirement.
The system also appears to rely on Xbox Live rather than calculating Mythic completion entirely inside the app. When a BaseGame group is finished, the app can process an “AchievementGroupCompletion” push notification containing information including the title ID, group ID, group type, completion time and achievements in the group. That notification then triggers the Mythic animation and dedicated unlock sound.
The feature remains disabled behind an “EnableAchievementGroups” flag, and the public achievements service does not yet appear to be supplying populated BaseGame groups broadly. Testing cited alongside the app analysis found empty group data for several existing games, suggesting Microsoft has not activated the server-side portion for players. That means the presence of the complete interface and notification framework should not be mistaken for a public rollout.
The discovery builds on filters spotted in Xbox Insider builds on September 19 for “Completed Mythic Achievement” and “Incomplete Mythic Achievement.” At that point, the filters established the name but provided little information about how the system would work. The newly uncovered PC app implementation now provides substantially stronger evidence that Mythic is being designed as a game-completion status with its own presentation and tracking logic.
Such a feature would put Xbox closer to PlayStation’s Platinum Trophy concept, which has long given players a distinct reward for completing a game’s main trophy set. Microsoft has already experimented with similar ideas at the individual game level, including Gears of War: E-Day’s platinum-style completion achievement, but Mythic appears to be a platform-level system rather than a game-specific workaround.
Microsoft has not confirmed whether Mythic will award additional Gamerscore, profile rewards or any other benefit beyond the badge and unlock presentation. The app code found so far does not establish any separate reward value. It also remains unclear whether older Xbox 360 and Xbox One titles will receive BaseGame group assignments retroactively or whether the system will initially target newer releases.
Xbox continues to test several platform changes through its Insider program, including 1440p Remote Play and other recent Insider features. Mythic now appears to be another comparatively mature feature in that pipeline, with much of the client-side interface already present even though Microsoft has yet to announce a release date or activate the required server data.
