Firefox 40 with Windows 10 support is available to download

• Support for Windows 10
• Added protection against unwanted software downloads
• User can receive suggested tiles in the new tab page based on categories Firefox matches to browsing history (en-US only).
• Hello allows adding a link to conversations to provide context on what the conversation will be about
• New style for add-on manager based on the in-content preferences style
• Improved scrolling, graphics, and video playback performance with off main thread compositing (GNU/Linux only)
• Graphic blocklist mechanism improved: Firefox version ranges can be specified, limiting the number of devices blocked

Changed:

• Add-on extensions that are not signed by Mozilla will display a warning
• NPAPI Plug-in performance improved via asynchronous initialization
• Smoother animation and scrolling with hardware vsync (Windows only)
• JPEG images use less memory when scaled and can be painted faster
• Sub-resources can no longer request HTTP authentication, thus protecting users from inadvertently disclosing login data

HTML5:

• IndexedDB transactions are now non-durable by default
• Implemented AudioBufferSourceNode.detune to modulate playback rate in cents, a logarithmic unit of measure used for musical intervals

Developer:

• Improved Performance tools in the developer tools: Waterfall view, Call Tree view and a Flame Chart view
• New rules view tooltip in the Inspector to tweak CSS Filter values
• Console API messages from SharedWorker and ServiceWorker are now displayed in web console
• New page ruler highlighting tool that displays lightweight horizontal and vertical rules on a page
• Inspector now searches across all content frames in a page
• Kannada text does not display properly in built-in pdf viewer
• Various security fixes

Known Issues:

• If Firefox is restarted from an add-on install notification, on-going private browsing downloads might be canceled without warning (1185294)