SeaMonkey 2.53.8 (32-bit)

What's new in this version:

- Serious performance improvements and bug fixes
- Language attributes with country codes not recognized when building the Website Navigation Bar link toolbar
- Optimize SeaMonkey icons for speed and optional higher quality for branding
- Support from= option when opening email compose window from the command line
- Update subject handling and GenericSendMessage function in compose window
- All message windows should update when view preferences are changed
- Improve marking of multiple messages as read / unread
- Show version numbers again in the add-on manager by the partial backout of
- Update available networks in chatZilla
- Change default port for IRC via TLS/SSL to 6697
- Remove chatZilla and Lightning extension language packs and incorpate localisations within the main language pack
- Fix address drag and drop handling in compose window
- Further fixes for legacy generators and the deprecated for each statement in add-ons and the Add-on SDK
- For developers, fork DOMi repo into main SeaMonkey one which means no need to separately checkout the extension

SeaMonkey 2.53.8 contains (among other changes) the following major changes relative to SeaMonkey 2.49.5:
- The Bookmarks Manager has switched its name to Library, and now also includes the History list. When invoking History, the Library will be shown with the History list selected. The extensive modifications were needed because of Mozilla Gecko platform API changes.
- Download Manager has been migrated to a new API. Although it looks pretty much the same as before, the search option is missing and some other minor details work differently. The previous downloads history is removed during the upgrade.
- The layout panel was added to the CSS Grid tools
- TLS 1.3 is the default SSL version now.
- Support for all NPAPI plugins like Flash, Java and Silverlight has been removed. For displaying pdf files in the browser you can use pdf.js-seamonkey from Isaac Schemm.
- SeaMonkey now uses a new api for formatting regional data like time and date. Default is to use the application locale of the current SeaMonkey build. If you use a language pack or a different OS formatting this is usually not desired. You can change the formatting from the application locale to the regional settings locale (OS) in the preferences dialog under "Appearance".
- SeaMonkey 2.53.8 uses the same backend as Firefox and contains the relevant Firefox 60.8 security fixes
- SeaMonkey 2.53.8 shares most parts of the mail and news code with Thunderbird. Please read the Thunderbird 60.0 release notes for specific changes and security fixes in this release.
- Additional important security fixes up to Current Firefox 78.11 ESR and a few enhancements have been backported. We will continue to enhance SeaMonkey security in subsequent 2.53.x beta and release versions as fast as we are able to.