Zig 0.16 has been released, billed as a major change. This release covers major changes to the language, the standard library, the build system, the fuzzer, and the toolchain.
Note that I am not a Zig developer myself. I'm summarizing the changes as I understand them, for an ecosystem in which I have an interest but in which I cannot claim membership; any errors in information here are mine, and I welcome correction by people who know better.
The language changes include, most severely, the deletion of GenericReader, AnyReader, and FixedBufferStream along with a wholesale redesign of how I/O is abstracted. This is a lot of why this looks like a major release despite being "0.16." Other changes include deprecation of C translation mechanisms (migrating to the build system instead of the source), changes to the type system, changes on how packed types behave, and restrictions on vector indexes.
There's also a new ELF linker, as part of a self-hosted toolchain; incremental compilation to improve the compile/test loop for larger projects, an internal fuzzer to help debug the toolchain itself, even LLVM 21 inclusion, although apparently this brought about a change in loop vectorization (the restriction from the previous paragraph.) This is notable mostly because of the transparency it shows, which is admirable, even if you might want to rely on the feature.
The type changes seem relevant, too, because they help the compiler describe better ergonomics around error conditions; the new type descriptors can tell you what you actually did wrong in an error message rather than point to a cryptic @Type(.{ .int = .{ .signedness = .unsigned, .bits = 10 } }) descriptor.
If there's a concern here, it's in the numbering system: a roadmap to 1.0 exists but it's unclear. It's hard for me to tell how far along it is, although 0.16 represents what looks like a significant investment in a workable future. Being willing to change things like this to create a measurable quality-of-life improvement is admirable.