Release notes
These release notes are summaries of the most important changes for public releases.
Published 2026-06-14
UXP Changes:
- Fixed a webaudio channel mixing regression resulting in broken audio.
- Added
powerPreference to canvas WebGL context
for web compatibility.
- Implemented support for the
lch color space
in CSS.
- Added a base implementation for CSS stylesheet constructors.
- Added a base implementation for CSS
aspect-ratio
sizing.
- Added support for CSS
min(), max()
and clamp() functions.
- Added support for CSS logical border radius properties.
- Added support for ranges in CSS media queries.
- Added support for CSS shadow parts.
- Added support for degenerate CSS values
infinity,
-infinity and NaN.
- Implemented full LoongArch64 Baseline/Ion/WASM JIT compiler
support.
- Added AV1 decoding with Dav1d for more performant AV1 video.
Note: AV1 is now enabled by default on non-x86 Basilisk builds.
- Added ES2024 Arraybuffer transfer APIs (
resize,
transfer, transferToFixedLength, detached,
maxByteLength and resizable).
- Added support for growable/resizable SharedArrayBuffers and
DataViews.
- Added ES2024 grouping builtins (map
.groupBy).
- Added ES2024 resolver builtins (
.withResolvers()).
- Added ES2024 String well-formed functions (
.isWellFormed()
and .toWellFormed()).
- Added support for symbols as weak collection keys.
- Added support for
Atomics.waitAsync.
- Added support for
FinalizationRegistry (part
of the WeakRef spec).
- Switched our build system to Python 3. See implementation
notes.
- Linux: removed
dbus-glib dependency.
- Linux: Added EGL as a preferred OpenGL provider with GLX
fallback; GLX remains the configured default as there are still some
unresolved issues with EGL.
- Improved JS performance by porting across various
enhancements from Mozilla.
- Fixed various application crashes.
- Further improved compatibility with building for Loongson
architectures.
- Further improved hardware accelerated decoding of WMF
videos.
- Fixed ARM assembler issues in the Goanna back-end.
- Improved parallel JS parsing tasks.
- Improved CSS handling of
calc() for web
compatibility, allowing it in many more places (e.g. color()
and z-index).
For compatibility and performance reasons, we still strongly recommend
that you use CSS variables to make calculations where possible.
- Ported several smaller performance improvements from the
Dactyloidae project.
- Aligned CSS
border width calculations with
mainstream, for web compatibility. Please note that this may impact
some themes that might rely on fractional border rounding (instead of
truncation).
- Removed the CloudFlare workaround as
it should no longer be necessary with general image size handling
improvements. The preference will no longer do anything.
- White-listed driver vendors for VMWare, VirtualBox, VirtIO
and Parallels to allow hardware accelleration as much as possible in VM
environments.
- Changed the implementation of
WeakRef support
to be always enabled in its full implementation (this was already enabled in Basilisk by default).
- Fixed some build issues on NetBSD.
- Mac: Fixed a pertinent crash due to font handling on OS X
10.7 through 10.11.
- Mac: Fixed build compatibility with 32-bit MacOS and Mac on
PowerPC hardware.
- Fixed a devtools crash on Big Endian machines.
- Fixed an issue causing rendering artifacts on excessively
large
border-radius values (e.g. Tailwind CSS).
- Fixed a stack corruption issue in
nsLocaleService
that could lead to crashes.
- Implemented some ANGLE upstream fixes.
- Fixed a regression that would cause crashes to
desktop when using certain extensions or visiting certain websites.
- Updated NSS to 3.90.11 (UXP), picking up a number of
upstream security fixes.
- Fixed potential security issues with audio channel mixing,
MP3 decoding (DiD),
international text display, DOM workers (DiD), reading of files (DiD), and the ANGLE graphics
library.
- Another large security audit was performed of 190
security-sensitive reported bugs. Many
security issues were addressed, including potential crash scenarios and
code correctness issues.
As a summary: 18 potential vulnerabilities were found applicable and
fixed, another 18 issues had DiD
code changes applied, and 4 were already mitigated by us before being
reported. Of the reported security bugs, 150 were not applicable to our
code (with a good portion once again pertaining to e10s/multi-process
browser
architectures).
Basilisk Changes:
- Fix an issue when searching with CTRL/CMD+F in PDF files opened in PDF.js.
- Enable dom.serviceWorkers.enabled pref by default
- Fix a bug where if Basilisk is set to not remember history and is set as the default PDF app for the OS, it will loop and open a bunch of tabs over and over when trying to open a PDF file in PDF.js.
- Remove leftovers from Firefox's "remote troubleshooting" functionality as it is not used by Basilisk.
- Remove FinalizationRegistry polyfill as UXP natively supports this function now.
- Port all Basilisk Python files to Python 3.
- Built on UXP commit: 83826f1f34
Included Polyfills:
-
This release includes the following polyfills:
- image.decode
- Intl.DisplayNames
- Intl.Segmenter
- en-US only Intl.ListFormat
- Microsoft-specific (Outlook, Azure, etc) webauthn shim
- TestDecoderStream
- TextEncoderStream
- TransformStream
- ReadableStream pipeTo
- ReadableStream pipeThrough
- getAnimations
- elementFromPoint finite values
UXP Implementation Notes:
- The Dav1d AV1 video library was added to UXP, which
allows for greatly better performance in AV1 video playback, especially
at higher resolutions. The codec is still very computationally
intensive, so this does rely pretty heavily on having modern, capable
hardware.
As an additional note, this library requires AVX hardware to properly
decode at speed. Due to the fact that Basilisk targets pre-AVX hardware, all x86 and x86_64 builds are configured to still use libaom.
If you build from source, there is a new configure option --enable-libaom
to build with the reference library instead of Dav1d.
- If you build from source yourself, you will no longer have
to rely on a
distribution that offers Python 2.7. Please note there is some variance
in Python 3 versions and not every version will work due to feature
changes within the Python 3 range. Versions 3.4 through 3.14 should work; YMMV on other
versions. Please ask for help on the forum if you can't figure it out.
Old Releases
Old release notes from Basilisk Development Team releases can be found
here.
Release notes from releases by Moonchild Productions can be found
here.
