Nexus 3.5.3 — a big update since 3.0.13.

NEW
• Right-click menu: “Summarize with Nexus” and “Reply with Nexus” in the message list; “Translate selection” and “Summarize selection” on selected text. In the composer, a translated selection replaces the selected text.
• Summarize several selected emails at once (overview, one line per email, pending actions).
• Nexus in the Spaces toolbar: a full-size tab without the popup size limit.
• “Open in a window”: Nexus in its own window that stays open when you switch apps.
• Nexus adapts to where it is opened: reading an email, in a reply, or in a new email.
• Reading an email: “Reply” and “Reply all” open Thunderbird’s reply with the generated text, keeping the quoted original.
• “With context” switch for Summarize and Reply (whole conversation, including Sent, or just the latest email).
• Reply language: Original (the email’s language) or your own; additional instructions always take priority.
• “Insert” now places the text at the cursor in the composer.
• Model list read from your OpenAI account; supports gpt-5 and reasoning models (default: gpt-5-mini).
• New interface (dark/light), redesigned settings, and a what’s-new history.
• Now in 7 languages: English, Portuguese, Spanish, French, German, Italian and Japanese, each with a rewritten manual.

KEYBOARD SHORTCUTS
• Shortcuts now actually work: they open Nexus on the right tab, and changes are saved in Thunderbird.
• New conflict-free defaults: Alt+Shift + the action’s initial (⌥⇧ on macOS). Hold ⌨ or Alt/⌥ to see them.

PRIVACY
• Nexus asks for explicit permission before the first request sends content to OpenAI; you can withdraw it at any time in Settings.

FIXES
• “Insert into composer” no longer closes the message view.
• Fixed detection of the original message when replying.
• “Translate/Summarize selection” now carries the selected text.