Chatto 0.5.0 is here! 🎉

Desktop apps, bots, search, and a whole new way to write: Chatto 0.5 brings a lot to your community. This release adds new ways to connect people and tools, catch up on conversations, and make Chatto feel like home.

Thank you to everyone who tested the previews, reported bugs, and helped get 0.5 ready!

These highlights cover the changes since 0.4.26, the previous stable release. Read the full release and upgrade guide before you upgrade an existing server.

Desktop app

• Chatto now has desktop apps for macOS, Windows, and Linux, with automatic updates, native notifications, and screen sharing. Download the app for your platform from the assets below.
• Linux screen sharing supports Wayland. The macOS release is for Apple Silicon.

For users

• Find old conversations with built-in search. Search one room, one server, or all your connected servers when their operators enable search.
• Choose between the Visual Composer and a new Markdown source editor. Both have a formatting toolbar. Messages now support Markdown tables and footnotes, plus Mermaid diagrams, SVG images, and ANSI art in code blocks.
• Catch up with a persistent notification feed. Activity stays until you dismiss it, and new notification settings let you choose how much each room interrupts you. Push notifications also work for remote servers.
• Use threads the way your room needs them. Rooms have four threading modes, and Post as thread creates a thread with its first message. Open a thread beside the room in a pane you can resize.
• Upload attachments with visible progress. Zoom and pan through images in the new viewer, or choose to preview HTML attachments in a sandbox. Downloads keep the original file.
• Hear calls more clearly with voice boosting, an optional noise gate, and volume controls for each participant. Calls highlight the active speaker and let you pin a video tile.
• Make Chatto your own with accent colors, flat or 3D styling, and contrast settings. Chatto is now available in 22 languages.
• Pin messages, publish room notices, link rooms by typing #, and reorder your servers in the sidebar.
• Stay in the conversation through reconnects. Active members stay signed in, and the installed web app asks before it reloads for an update.
• Breaking Change: The 0.5 client cannot connect to 0.4 servers. New direct message conversations support two people; existing group conversations remain accessible. Use channel rooms for new group conversations.

For robots

• Bots are here! Bot accounts can post, reply, react, and receive direct messages through the same API as members. A visible BOT badge keeps them easy to identify.
• Bring external activity into rooms with incoming webhooks, including Grafana alerts without a custom template. Signed outbound webhooks notify your integrations when someone mentions a bot or sends it a direct message.
• Build integrations with the framework-neutral @chatto/client TypeScript package. It handles requests, live state, reconnects, and bot message handling.
• Connect AI assistants through the experimental built-in MCP server. Assistants act with the permissions of the member or bot that authorized them.
• Realtime protocol 4 starts with an exact snapshot and can resume after a short disconnection without a full reload.
• Breaking Change: Custom clients and bots must use the 0.5 protobufs and realtime protocol 4. Regenerate clients and follow the API compatibility guide.

For administrators

• Administrative and moderation permissions now require privileged mode, which lasts for 15 minutes. The event log records each activation.
• Control registration with invitation codes, and invite members into private rooms. Deactivate accounts to stop access while keeping their data, then reactivate or delete them when needed.
• Members can add several verified email addresses. Servers can use SSO-only login, restrict OIDC access by group, and map provider groups to Chatto roles.
• Recommend other communities with Neighbors in the Server Directory.
• Breaking Change: Review permissions when upgrading. Thread replies now use message.post, and an explicit role or user allow can override an everyone deny. Grant the new bot and invitation permissions where needed, review delegated room management, and check owner access under privileged mode. The permission upgrade checklist gives the required grants and migration details.

For operators

• Set up a new server in the browser, including its name and owner account. The first login does not require email delivery or a command line.
• Servers with long histories replay faster and use less memory. Optional encrypted snapshots can shorten restarts further.
• Use chatto init for guided configuration and chatto config check to find unknown or deprecated settings. Diagnostics now show background worker health, asset cleanup, and LiveKit setup information.
• Enable search through [search] and [search_provider]. Search stays off by default.
• Send transactional email through JMAP, create browser-compatible previews for HEIC uploads, and show community counts with Shields.io badges.
• Breaking Change: Back up your server before upgrading, including S3 assets and encryption keys separately. Plan downtime and upgrade the bundled client with the server. After 0.5 accepts traffic, a rollback to 0.4 requires restoring the backup.
• Breaking Change: Rename video processing settings to asset_processing.* and enable processing explicitly. Use core.assets.max_upload_size for all attachments; the default is now 25 MB. Remove the old asset cache settings and webserver.oauth_redirect_origins, and review allowed origins and the enforced Content Security Policy.
• Breaking Change: Scripts must replace --passphrase with --passphrase-file or --passphrase-stdin. Monitoring must use chatto_model_info instead of chatto_service_info.

See the complete upgrade procedure and configuration changes before deployment. Notification feeds start empty, notification settings use new defaults, and some clients must sign in again once.

Happy chatting! 🐙