Insiders in the Alpha Skip-Ahead ring can have gamertags up to 15 characters long.
Xbox
Xbox is rolling out a couple of new features to its Insiders in the Alpha Skip-Ahead ring, its invite-only tier that gets access to experimental builds earlier than any of its other testers. It's bringing back support for 15-character gamertags, after limiting them to 12 characters a few years ago, due to feedback from players who've been telling the Microsoft gaming division that they want more flexibility when choosing usernames.
As long as the gamertag they want to use is unique and available, it can have up to 15 characters. If they're not unique, and the system would need to add numbers to it because the base name is already taken, they can only have 12 characters. Xbox will continue to support 12 characters for any gamertag with non-Latin characters, as well.
Xbox has also added game hubs in the game cards for Xbox 360 titles. When Insiders open a game card for any of their installed 360 game, they'll see their achievement progress, captures and other pertinent information. They'll now also see detailed achievements for their 360 games on their profiles.
Another thing they can now enjoy is being able to play a game even if it's currently being updated. If the game they want to play is available to stream through their Game Pass membership, they can start playing immediately on the cloud while the update downloads in the background. They'll see the option to play on the cloud directly from the game card while it's updating. Finally, they'll be able to add released and upcoming games to their wishlist directly from game cards.
While the Alpha Skip-Ahead ring is invite-only, players can let Xbox know they're interested in participating by launching Insider Hub on their console, selecting Activities and scrolling down under Available until they see the "Joining new rings" option. They then have to complete a survey. Xbox says it looks at several factors to determine whether to send a user an invite, such as if they've submitted high-quality feedback, participated in quests and surveys, as well as much how much or what games they play.