Mastodon 4.6 RC adds Collections, full API endpoints, and ActivityPub upgrades

Mastodon has released the first release candidate for version 4.6, adding Collections, profile updates, API changes, and several Fediverse protocol improvements ahead of the final release. Collections let users create public, curated lists of recommended accounts, with names, descriptions, topics, and language settings to help with account discovery and onboarding.

The update adds new API endpoints for creating, managing, and updating Collections, along with notification types for collection activity. Profile management also gets dedicated editing endpoints, raw and formatted profile fields, and new settings for media and featured content tabs, giving client apps more control over how profile editing and display preferences are handled.

On the federation side, Collections and profile preferences are now represented through ActivityPub properties such as featuredCollections and interactionPolicy. Mastodon 4.6 also improves HTTP Signature handling, updates to API version 10, adds fallback notifications, exposes account and profile limits through the API, supports Wrapstodon reports, and implements FEP-2c59 and FEP-3b86 for better username validation and server-agnostic links for common actions.