Thunderbird 52.1.0

What's new in this version:

What’s New:
- Fixed: Clicking on a link in an email may not open this link in the external browser

Known Issues:
- Large number of blank pages being printed under certain circumstances
- Large attachments may not be shown or saved correctly if the message is stored in an IMAP folder which is not synchronized for offline use. Workaround: Set preference browser.cache.memory.max_entry_size to the value of -1 (unlimited) and create integer preference browser.cache.memory.capacity with the value of 200000 (200 MB, 25 MB per message).
- Crash due to incompatibility with McAfee Anti-SPAM add-on. Workaround: Start in safe mode and disable McAfee Anti-Spam Extension
- Background images not working and other issues related to embedded images when composing email
- Crash when compacting IMAP folder