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The Bat! v12.3 (28 July 2026)

New features

• Autocrypt Level 1 — opportunistic e-mail encryption with automatic peer-key tracking and send-time recommendations
• Markdown attachments: .md/.markdown files are tagged text/markdown and rendered as Markdown in ThreadView
• "Copy Image" command added to ThreadView and HTML message-viewer popups
• Key Manager can now add subkeys to an existing OpenPGP key
• Generate ECDSA/ECDH (NIST P-256) subkeys for existing OpenPGP keys
• Generate OpenPGP key and subkey revocation certificates
• Smart account select
• IMAP NOTIFY (RFC 5465): one monitoring connection now watches all mailboxes for changes
• IMAP UID MOVE (RFC 6851): server-atomic message moves with no transient duplicate
• OpenPGP keys now live in a transactional SQLite keyring (keyring.db) with on-demand lookups
• Text attachments are scanned for inline OpenPGP blocks, so Import Key / Decrypt / Verify are one click away
• Encryption now always includes the sending identity's key, so the Sent copy stays readable
• PDF Signatures support - verify, sign-and-reply, sign-and-save
• Encrypt and Sign now work in Conversation Thread View in the Quick Reply; toggles are seeded from account defaults
• Key-picker dialog is now displayed if several secret keys can decrypt the same message
• It is now possible to decrypt messages sent with hidden recipients (gpg --throw-keyids wildcard key IDs)
• "Copy Public Key" copies the selected key's armored public key to the clipboard in the PGP Key Manager
• Key Manager opens modeless — it no longer blocks the rest of the program or app exit

Improvements

• Copy/filter destination folder now updates incrementally instead of a full re-read
• Higher-contrast text selection color in pure-HTML view under the dark theme
• Auto-decrypt on thread load restored in the Conversation Thread View, silent-only — uses already-unlocked keys, never prompts
• Replying to an encrypted message now defaults the editor to Encrypt

Fixes

• Fixed iCloud calendar events all collapsing onto a single date/time (CalDAV multiget hrefs)
• Fixed iCloud CalDAV sync failing with 400 Bad Request on pathless server URLs
• Fixed CEF (HTML) views being disabled when The Bat! runs elevated ("As administrator")
• Zoom now works in the plain-text editor and in the CEF thread view
• Fixed an exception when replying from the Mail Ticker message list window
• Fixed calendar reply using a wrongly quoted recipient address
• Checked menu items were invisible in the Windows 11 light theme
• Fixed font color for color groups in the folder list
• Editor Toolbar buttons were invisible in a dark theme
• Accessibility: restored screen-reader (NVDA) support on Win64 (WM_GETOBJECT gate)
• Accessibility: date-group separator rows are now announced to screen readers
• Fixed garbled IMAP Subject/From/To/CC/BCC when servers return raw UTF-8 ENVELOPE (RFC 9051/6855/6532)
• Fixed non-ASCII text attachments appearing as mojibake in the thread-view preview (now decoded to UTF-8)
• Fixed long-dash auto-replace in the HTML editor
• Sent copy is always encrypted to the sender's own identity key, also when signing with the default key
• Decryption tries every matching own key instead of giving up after the first refused passphrase
• Encrypt dialog now states the real per-address reason a recipient cannot be encrypted to
• Replies to encrypted messages quote the decrypted text instead of the armored ciphertext
• Fixed passphrase dialog dropping the typed passphrase and selecting the wrong key on cancel
• Fixed mojibake in decrypted inline-PGP messages (UTF-8 rendered in system codepage) in Conversation Thread View
• Encryption/signature icons (rebuilt bundle with Material Icons font) in the Conversation View are restored
• Fixed date-time separator being trimmed when restoring from backup
• Fixed exception after previewing an ICS file, deleting the mail and moving to another folder
• Fixed OAuth authentication for Outlook.com and Microsoft 365

Revision History

The Bat! upgrade policy

• The Bat! v5 license purchased December 23, 2010 - September 25, 2013 is valid for a The Bat! v6.0 update only. For The Bat! v6.1 and higher these licenses are not valid.
• The Bat! v6 license purchased September 26, 2013 - November 25, 2013 is valid for a The Bat! v7.0 update only. For The Bat! v7.1 and higher these licenses are not valid.
• The Bat! v6 license purchased November 26, 2013 - May 8, 2015 is valid for all The Bat! versions 6. For The Bat! v7.0 and higher these licenses are not valid.
• The Bat! v7 license purchased May 9, 2015 – August 21, 2017 is valid for version 6.8 and all The Bat! versions 7. For The Bat! v8.0 and higher these licenses are not valid.
• The Bat! v8 license purchased August 22, 2017 – June 2, 2019 is valid for all The Bat! versions 7 and all The Bat! versions 8. For The Bat! v9.0 and higher these licenses are not valid.
• The Bat! v9 license purchased from June 3, 2019 - May 31, 2021 is valid for all The Bat! versions 8 and all The Bat! versions 9. For The Bat! v10.0 and higher these licenses are not valid.
• The Bat! v9 license purchased from June 1, 2021 - April 28, 2022 is valid for all The Bat! versions 9 and all The Bat! versions 10. For The Bat! v11.0 and higher these licenses will not be valid.
• The Bat! v10 license purchased from April 28, 2022 - May 31, 2023 is valid for all The Bat! versions 10. For The Bat! v11.0 and higher these licenses are not valid.
• The Bat! v10 license purchased from June 1, 2023 - December 20, 2023 is valid for all The Bat! versions 10 and all The Bat! versions 11. For The Bat! v12.0 and higher these licenses will not be valid.
• The Bat! v11 license purchased from December 21, 2023 - May 31, 2025 is valid for all The Bat! versions 11. For The Bat! v12.0 and higher these licenses will not be valid.
• The Bat! v11 license purchased from June 1, 2025 - December 30, 2025 is valid for all The Bat! versions 11 and all The Bat! versions 12. For The Bat! v13.0 and higher these licenses will not be valid
• The Bat! v12 license purchased from December 30, 2025 is valid for all The Bat! versions 12. For The Bat! v13.0 and higher these licenses will not be valid

Users who have a license for any version of The Bat! can update their license to The Bat! v12 by purchasing an upgrade.

Please note: We reserve the right to adjust our upgrade policy without notification.

The Bat! mail software supports the following versions of Windows Operating System:

Client versions

• Windows 10 (32/64 bit) - Certified for Windows 10
• Windows 11 (32/64 bit)

Server versions

• Windows Server 2016 & R2
• Windows Server 2019