At CES 2024, KaiOS discussed 5G smart feature phones “slated for an early 2025 rollout” in partnership with Qualcomm.
KaiOS 4.0
KaiOS 4.0 is the next major version of KaiOS, expected to be released in 2025. Hints have been discovered in user agent logs and online forums. KaiOS 4.0 made it’s first appearance on the KaiOS Developer Portal in April 2024. Here what we know so far:
- Support for 5G
- Upgraded chipset ( Qualcomm SM4635)
- Updated to Android 14 base
- Upgraded to Gecko 123 engine
- Same APIs as KaiOS 3.0
- Initial markets: India, USA (possibly as the Go Flip 5)
- Improved support for eSIM (commits
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Behind the Scenes
KaiOS 4.0 isn’t expected to have many developer-facing changes. No major changes in B2G APIs, no changes to how hosted or packaged apps are served on the http://*.localhost origin, and no fundamental changes in the user interface. However, with all major upgrades in underlying technology, compatibility issues and breaking changes are expected.
Total Cookie Protection: Firefox v86 rolled out
Total Cookie Protection by default to most users. In KaiOS 2.5, all cookies were globally-scoped and shared between apps and the browser unless the
sandboxed-cookies permission was used. Sandboxed cookies because the default (and only) behavior in KaiOS 3.0. KaiOS 4.0 will take this a step further by creating a separate “cookie jar,” for each unique origin. This may further restrict the ability to share information using cookies between packaged apps on the origin http://*.localhost and their corresponding websites https://myapp.com.
New Features: Because KaiOS 4.0 will upgrade to the Gecko 123 engine (released February 20, 2024), new features are expected including support for the declarative Shadow DOM, enabled by default in v122. Also expected is support for the AVIF image format (and AV1 images with animations). It’s possible KaiOS 4.0 will support the Clipboard API, making it one of the first feature phone platforms with copy-paste functionality. Unfortunately, zstd (zstandard compression) support didn’t make it until Firefox v126.
More Privacy: Firefox v85 introduced protections from supercookies and v87 introduced a trimmed HTTP Referrer header, by default. v88 isolates window.name data and v119 partitions Blob URLs.
Conclusion
KaiOS 4.0 is expected to be primarily a behind-the-scenes upgrade for major markets where 5G support is valuable. Although it should support most KaiOS 3.0 apps, subtle changes in the Gecko engine and privacy configurations may cause hard-to-detect bugs. If you’re looking for an experienced partner to maximize reach across the feature phone market, contact the author from the About page.