From Go 1.22 to 1.27: Loop Variables, Routing, range-over-func, Green Tea GC, json/v2 and Generic Methods
In Go, the go line in go.mod and GODEBUG settings decide a release's behaviour, but removed settings end that protection: because Go 1.27 removed asynctimerchan, the timer behaviour of a module saying go 1.22 changed with nothing but a toolchain upgrade. The changes from 1.22 to 1.27 that matter for backend work, the nil check fix, os.Root, uuid, measuring the new allocator, what moving to json/v2 does to clients, and go fix modernizers.
15 Nov 2026
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15 min
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5
