Level 4
With Pale Moon 25.0, support for the Windows XP operating system has been dropped. This page aims to clarify the situation and provide alternatives to current Windows XP users who wish to continue using Pale Moon as their browser.

Why was Windows XP support discontinued by Pale Moon?
Unlike its sibling Firefox, that will continue to offer Windows XP as a supported operating system, Pale Moon has discontinued support for this OS. Considering the large number of users still on Windows XP, this has not been done without some good reasons, outlined below:
  • OS security considerations: Windows XP is no longer supported or maintained by its developer (Microsoft) and lacks continued security updates that are needed in this day and age of malware. It's considered End of Life since April 2014, and using it is inherently taking a risk. Pale Moon should not support situations where the user puts themselves at risk. Consider it a nudge to move on.
  • OS Life considerations: Windows XP has the status "obsolete". It has never been one of Pale Moon's goals to support particularly old systems from its very inception. That includes obsolete operating systems.
    There is an alternative version of Windows XP called POSReady2009 that will receive continued updates beyond this point in time, but it should be noted that this is not a desktop operating system and has been designed specifically around use in cash registers and other Points of Sale situations with single-application use (and not desktop use) in mind. Using that alternative version is never recommended for general use and is not considered by Pale Moon as a viable target operating system to run on.
  • Stability considerations: Forcing NT 5.x kernel compatibility has shown to cause stability issues, especially with the optimizations used in Pale Moon's main-line builds. Being able to use more modern (Vista and later) windows functions improves stability and overall performance of the browser.
  • Compiler support: Windows XP support was only added as an afterthought to the compiler in use by Pale Moon (Visual Studio 2012). This support for Windows XP has never been part of the compiler's design and the resulting binaries in this forced compatibility are at least suboptimal and at most prone to severe compiler bugs and crashes.
  • Graphics subsystem compatibility: Pale Moon's graphics subsystem is really aimed at being able to use DirectX 10 or later, something that is not available in Windows XP. Apart from having to build in all sorts of workarounds for DirectX 9 (the highest version supported by Windows XP) and the inherent problems with that, it also means that nobody on Windows XP will be able to benefit from the acceleration and graphics features available in later operating systems. Users on Windows XP are therefore already running on "extended backwards compatibility" and this part of the graphics subsystem is not really maintained or updated anymore.

What are my alternatives?
There are a few alternatives to consider, and a few (although logical) things that are not recommended:
  • Recommended: Of course the top recommendation is to upgrade to a later operating system. Windows 7 is strongly recommended in this case for current users of Windows XP. It will be supported until 2020 and provides the most familiarity and customizability that Windows XP users would be looking for. On top, it is a very stable and well-rounded operating system. Once you have upgraded, running current and future versions of Pale Moon will not be an issue.
  • Recommended: Since the specialized Atom version will continue to support Windows XP (because of the large amount of netbooks being limited to that operating system) you can switch to that version.
  • Recommended: If you are looking for a full main-line build of Pale Moon with Windows XP support, there are also 32-bit and 64-bit alternative (third-party) builds of the browser specifically maintained for Windows XP and Server 2003 environments. Please do note that these versions will be discontinued when the last retail NT 5.x product goes EoL in July 2015.
  • Of course another alternative is to switch browser. We will be sad to see you go.
  • Not recommended: stay on Pale Moon 24.7.2. With the release of Pale Moon 25.0, simply "not upgrading the browser" is not recommended because the previous major version will not receive updates or further support. We simply do not have the manpower or resources to continue updating and maintaining multiple different versions of the same product. If you stay on Pale Moon 24.7.2, you will not receive any security and stability updates that the current version receives, and you will put yourself at (even greater) risk.
  • Not recommended: attempt to build your own from source. Building Pale Moon from source is not extremely difficult but it will require some advanced knowledge, since you will have to make edits to the source code to enable Windows XP compatibility before building. In addition, we will not provide any support for your own builds so you are pretty much "on your own" if you run into trouble.




Level 4
PaleMoon 25 released, and Release Notes ....

Pale Moon: Release notes
25.0.0 (2014-10-10)
Pale Moon 25.0 is a new major release with a large number of changes. A summary of the most important changes can be found here; for more details about this release, please check the forum.

  • Change of the browser's GUID (Globally Unique Identifier) to properly differentiate from Firefox.
    The new GUID is {8de7fcbb-c55c-4fbe-bfc5-fc555c87dbc4}.
  • Allow extensions with both Pale Moon GUID and Firefox GUID to be installed natively (dual-ID system).
    Pale Moon GUID blocks will have preference over Firefox (compatibility) blocks.
  • Disconnect of Pale Moon's "Firefox compatibility" version from Pale Moon's application version to maintain Firefox 24.* extension compatibility regardless of Pale Moon version.
  • Disable Firefox Compatibility mode by default.
    This means Pale Moon will no longer have a Firefox/xx.xx indicator in its UserAgent string.
    This may impact some websites that check browsers by UserAgent and possibly warn, complain or block you. You should contact the site's owners and request support for Pale Moon. Pale Moon will allow you to override the UserAgent on a per-site basis if you absolutely must visit the site and they absolutely won't cater to your freedom of browser choice.
  • Use the alternative sync implementation on a new server.
    Current Pale Moon sync accounts cannot be ported over, so you will have to create a new account when updating to v25.
    The previous server implementation has already been shut down due to continued issues, and will be retired on the very short term to free up infrastructure and reduce expenses. The alternative sync implementation is Sync 1.1 compatible, like before.
  • Stop building the WebApp runtime by default.
    The use of "Web Applications" started from the command-line is such a niche feature that it has no business being in Pale Moon's main-line builds.
    If you need the WebApp runtime for your specific organization and want to use Pale Moon, you can build Pale Moon from source with the feature enabled.
  • Stop supporting Windows XP. As mentioned a few times before, Pale Moon's support for Windows XP (and any other NT 5.x based operating system) has now ended. An exception to this is the specialized Atom build because of limited operating system availability on netbooks and the like. More details on the dedicated page for this change.
  • By default, do not sync add-ons.
    Syncing between different devices will likely not want you to sync the add-ons in use. There's a reason you're using different devices, after all.
  • Un-prefix CSS box-sizing.
    You can now use box-sizing:border-box, box-sizing:padding-box and box-sizing:content-box to switch box-sizing mode on elements using CSS.
  • Implement image-orientation in CSS.
    You can now use image-orientation: {angle} [flip] in CSS to rotate images in 90 degree steps and optionally flip them.
  • Improve bookmark menu item-dragging.
    Dragging bookmarks in the bookmarks menu is now more convenient (allow diagonal dragging, prevent tooltips from interfering, etc.).
    (Fixes bugs 225434, 419911 and 555474)
  • Move the option to "use the classic downloads window" from status bar preferences to the main options window.
    This way, it's easier for people to find and it's in a much more logical place. The classic downloads window will not go away any time soon in Pale Moon.
  • Update branding images for official/unofficial logo, and some about: pages.
  • Add a new type of "blank new tab" page with logo-styling.
    This logo page will be the default setting (instead of about:blank).
  • Add Opus audio to WebM.
  • Add VP9 codec to WebM on both desktop and Android/ARM.
  • Allow absolute-in-relative positioning in table and CSS table-cell elements.
  • Allow the user to override the use of accessibility colors in the browser with browser.display.ignore_accessibility_theme
  • Improve the display of tabs when lightweight themes (personas) are in use for both light and dark themes.
  • Enable cache compression by default to more efficiently use disk cache.
  • When shutting down the browser while you still have downloads in progress, Pale Moon will now by default warn you that the downloads will be cancelled.
  • Added language packs for Acholi, Assamese, Kashubian, Pulaar Fulfulde, Armenian, Khmer, Ligure, Mongolian, and Swahili.
Bug/regression fixes:
  • Prevent error in removeobserver() for the padlock code when closing a window
  • Hang fix: Release XPCOM timer immediately after firing to prevent a race condition. (CVE-2014-1553)
  • Android & any ARM processor: Always use integers for audio instead of floats.
  • Properly apply the use of high contrast themes on Windows 8/8.1
  • Prevent the accumulation of hidden about:blank windows in some situations.
  • Android: prevent deadlocks due to invalidations when using plugins (Flash)
  • Re-enable high-quality downscaling of particularly large images (selective HQ downscaling) and improve fast image scaling method (use Lanczos instead of Hamming)
  • Hang/DoS fix: Avoid uninterruptable infinite loops in IonMonkey in some situations. (CVE-2014-1548)
  • Android: improve the handling of zooming to input fields
Security fixes:
  • Properly derive/insert the host of a URL
  • Avoid negative audio ratios (can lead to crashes) (CVE-2014-1565)
  • Avoid some root hazards in the style parser
  • Add is-object check to IonBuilder::makeCallHelper (CVE-2014-1562)
  • Clear the jumplist icon cache when history is cleared (privacy fix)
  • Crash fix on Windows (JS JIT) (CVE-2014-1554)
  • Prevent buffer overrun in text directionality component (CVE-2014-1567)
  • Update NSS to (CVE-2014-1568)

It's very sad news for me, because i am using PaleMoon as secondary browser in Windows XP installation, Comodo firefox version [icedragon] is not updated, looks like no other firefox based stable lite browser available :(