There was a lot of discussion around Safari 15.4 beta supporting Web Push on iOS but a ton of other great highly demanded features are coming.

Just a few highlights:
* RegExp lookbehind assertions
* outline following border-radius
* Declarative Shadow DOM
* WASM SIMD
* OffscreenCanvas (2D only for now)

Check out the beta or a recent STP release. We welcome feedback, including what you’d like to see next.

https://developer.apple.com/documentation/safari-release-notes/safari-16_4-release-notes

@othermaciej how can I check for webgl support in OffscreenCanvas? Do I really have to do UA sniffing and know that Safari doesn’t support it?

@sto3psl I think you can feature test this directly by trying to make a GL context for an OffscreenCanvas - it will error out if this combo is not available.

@othermaciej I tried and it doesn’t error 🙈. I still get a GL context from the OffscreenCanvas but everything renders broken (because the feature is not ready, I guess).

@sto3psl This was a bug in an earlier beta. The intent is that OffscreenCanvas will not support "webgl" contexts regardless of whether it's on a worker. Expect to see that fix in an upcoming beta, it should allow for easier feature detection. (Sorry, I didn't realize it hadn't been in a beta yet). https://bugs.webkit.org/show_bug.cgi?id=253267