Opt-in tabbed multi-pane interface for power users. Open multiple mail, calendar, contacts, and file views side-by-side, drag tabs to reorder or split panes at the edges, and work across all logged-in accounts in one shell, cross-account email moves, a unified inbox with search, account-split calendar/contacts/files sidebars, and a per-account "From" dropdown in the composer. Enable from Settings β Appearance; the proInterface preference is per-device and not synced.
Pro mode is experimental and we need your feedback to shape it. If something feels off, breaks, or is missing, please don't hesitate to open an issue or start a discussion on GitHub!
Breaking Changes
Plugins: Plugins now run inside a null-origin iframe sandbox and talk to the host over a postMessage RPC bridge. The in-process plugin runtime is gone; the bundled in-tree plugins have been migrated. Third-party plugins built against the old in-process API need to be ported to the sandboxed runtime.
Plugins: Server-managed bundles must be Ed25519-signed by the host and approved by an admin before they load. The host public key is served from /api/plugin-signing-pubkey and each bundle response carries the signature in the X-Bundle-Signature header. User-uploaded bundles still load unsigned, but managed marketplace and dev-folder bundles do not.
Plugins: bundleHash is now a full SHA-256 over the bundle. Legacy short hashes are migrated on first load; any out-of-band tooling that pinned the old hash format needs to be updated.
Features
Pro: Tabbed shell with drag-to-reorder, drag-to-edge to split, side-by-side panes, and pane-aware responsive layout with a scoped sidebar overlay
Pro: Auto-redirect to the Pro shell when Pro mode is on; proInterface is kept per-device instead of syncing
Pro: Multi-account mail sidebar with client routing and a per-account mailbox cache
Pro: Unified mailbox always visible, with full-text search
Pro: Cross-account email moves
Pro: Multi-account calendar sidebar split into owned vs shared per account
Pro: Multi-account contacts and a cross-account file picker
Pro: Composer From dropdown grouped by account
Plugins: Per-plugin admin approval workflow with Ed25519 bundle signing verified on load
Plugins: Marketplace update flow for installed plugins and themes
Setup: Allow the setup wizard over plain HTTP with a dismissable warning gate
Setup: Warn when the JMAP URL points at a local-only host
Account: List and reorder logged-in accounts from settings (#282)
Mail: Mobile handoff page with JMAP authentication verification for cross-device OAuth