Requirements: Windows XP / Vista / Windows 7 / XP 64-bit / Vista 64-bit / Windows 7 64-bit / Windows 8 / Windows 8 64-bit / Windows 10 / Windows 10 64-bit
What’s New Fixed: Various Theme fixes where incorrect colors, backgrounds, etc. were displayed. Add-on Options menu not working on Mac. Shift+PageUp/PageDown in Write window. Saving content of Write windows didn't overwrite existing file. Issues related to "Edit Template" command. Gloda attachment filtering. Mailing list address auto-complete enter/return handling. Thunderbird hung if HTML signature references non-existent image. Filters not working for headers that appear more than once. Various security fixes.
Known Issues Unresolved: According to RFC 5721, passwords containing non-ASCII characters are encoded using UTF-8 which can lead to problems with non-compliant providers, for example, office365.com Double-clicking on a word in the Write window sometimes launches the Advanced Property Editor or Link Properties dialog. CalDav access to some servers not working. Workaround: Set preference network.cookie.same-site.enabled to false. Chat: Twitter not working due to API changes at Twitter.com (solution forthcoming).