Go 1.26: What's New

Go 1.26 shipped in February 2026, six months after Go 1.25, keeping the Go 1 compatibility promise. Here's what stands out.

Language changes

new() now accepts expressions, not just types, to set an initial value:

type Person struct {
    Name string `json:"name"`
    Age  *int   `json:"age"`
}

p := Person{Age: new(yearsSince(born))}

Self-referential generic constraints are now allowed — a generic type can reference itself in its own type parameter:

type Adder[A Adder[A]] interface {
    Add(A) A
}

func algo[A Adder[A]](x, y A) A {
    return x.Add(y)
}

Tooling

• go fix was rewritten around "modernizers" — dozens of fixers that update code to modern Go idioms/APIs — plus a source-level inliner driven by //go:fix inline directives.
• go mod init now defaults to a lower go version in go.mod (Go 1.26 writes go 1.25.0).
• cmd/doc / go tool doc are gone — use go doc.
• pprof's web UI now defaults to the flame graph view.

Runtime

• Green Tea garbage collector is on by default (experimental in 1.25) — 10–40% less GC overhead, with an extra ~10% on newer CPUs (Intel Ice Lake, AMD Zen 4+). Opt out with GOEXPERIMENT=nogreenteagc.
• cgo calls are ~30% cheaper at baseline.
• Heap base address randomization on 64-bit platforms, a security hardening measure (GOEXPERIMENT=norandomizedheapbase64 to disable).
• An experimental goroutine leak profile (runtime/pprof, enabled via GOEXPERIMENT=goroutineleakprofile) flags goroutines blocked on unreachable concurrency primitives, exposed at /debug/pprof/goroutineleak.

Standard library

Two new packages: crypto/hpke (RFC 9180 hybrid public-key encryption, with post-quantum support) and the experimental simd/archsimd (SIMD on amd64).

A few changes worth knowing about:

Package	What changed
crypto/tls	Hybrid post-quantum key exchange on by default
crypto/mlkem	~18% faster encapsulation/decapsulation
io.ReadAll	~2x faster, ~50% less allocation
bytes.Buffer	New Peek() method
net	New Dialer.DialIP/DialTCP/DialUDP/DialUnix
reflect	New iterator methods: Fields(), Methods(), Ins(), Outs()

Platform notes

Go 1.26 is the last release supporting macOS 12 Monterey (Go 1.27 will require macOS 13+), and the Windows 32-bit ARM port is gone. Bootstrapping Go 1.26 itself requires Go 1.24.6 or later.

Full details: go.dev/doc/go1.26.