Update: Version 27.0.1 was released to fix some of the issues that popped up with the new milestone.
As explained in the Release Notes, Version 27 is a full upgrade of the back-end platform. This means that many things work different "under the hood". As a result, you may run into a number of extension compatibility issues and may wish to run the v27 Compatibility Checking Tool. Also note the "Removed/support features" in the Release Notes.
Edit Note: If you are having problems with the upgrade, see Some known issues when upgrading to Pale Moon 27.
Details from the Release Notes:
- All relevant security fixes up to and including Firefox 50 have been ported across from Mozilla to continue to provide an as secure as possible browser.
- Several libraries have been updated to their latest versions to pick up any important vulnerability fixes.
- There's a new option and control to determine whether to save zone information (marking files as "downloaded from the Internet") on downloaded files (Windows+NTFS). You can find this in Options.
- Support for DirectX 11 and Direct2d 1.1 on Windows. This will bring Pale Moon more in line with the capabilities for current-day operating systems and graphics hardware.
- Update of the Goanna engine to 3.0 - with many changes to layout and rendering for the modern web.
- Pale Moon now fully supports HTTP/2.
- Ruby Annotations are now an integral part of the HTML parser, controllable with CSS.
- Media Source Extensions have been implemented to solve many video playback issues.
This can be enabled/disabled and configured in Options. It's recommended at this time to not enable MSE for WebM since there are a few issues with it on services like YouTube (e.g. losing audio when looping/skipping).
- Support for reading and playing so-called "fragmented" MP4 files has been added, further solving media playback issues.
- Support for SSL/TLS connections to proxy servers.
- Support for the WOFF2 font format for downloadable fonts.
- The way web content is cached has been changed to be more efficient. If you want to immediately take advantage of this, clear your cache.
- Windows Vista/Windows 7/8/10/Server 2008 or later
- Windows Platform Update (Vista/7) strongly recommended
- A processor with SSE2 instruction support
- 256 MB of free RAM (512 MB or more recommended)
- At least 150 MB of free (uncompressed) disk space