Go 1.21

This version has reached end of life and no longer receives updates.

End of Life

Released

August 8, 2023

Active Support

Ongoing

End of Life

August 13, 2024

Latest Patch

1.21.13 (August 6, 2024)

About Go 1.21

Go 1.21 introduced the standard library log/slog package for structured logging, built-in min/max/clear functions, and profile-guided optimization (PGO) enabled by default.

Key Changes in Go 1.21

●log/slog: structured, leveled logging in the standard library (no more third-party loggers for basic needs)
●Built-in min(), max(), and clear() functions
●Profile-guided optimization (PGO) enabled by default (2-7% performance improvement)
●Forward compatibility: go.mod go line becomes a minimum version requirement
●New maps and slices packages in stdlib

Breaking Changes

▲Go line in go.mod now enforces minimum version (may affect builds with older Go versions)
▲Loop variable experiment available via GOEXPERIMENT (later default in 1.22)

Go 1.21 reached end of life on August 13, 2024, roughly 1 year ago. Since then, no security patches have been issued. If you are still running Go 1.21, you should treat upgrading as a high-priority item. Any CVEs discovered against this version will not be fixed upstream.

The recommended upgrade target is Go 1.26. You are 2 major versions behind, so review the changelog for each version in between to catch any breaking changes. A staged upgrade through each major version is often safer than jumping directly.

Migration Notes

Go 1.21 is backwards compatible. The main change to be aware of is PGO being on by default (can increase binary size slightly). If you use a default.pgo file, it will be used automatically.

Official Release Notes Check for vulnerabilities Check your full stack for EOL

Lifecycle Progress

Released: Aug 2023 EOL: Aug 2024

This version reached end of life August 13, 2024.

Previous Version

Go 1.20

End of Life Next Version

Go 1.22

End of Life

All Go Versions

Version	Released	EOL	Latest	Status
1.26	February 11, 2026	TBD	1.26.0	Active
1.25	August 12, 2025	TBD	1.25.7	Active
1.24	February 11, 2025	February 11, 2026	1.24.13	End of Life
1.23	August 13, 2024	August 12, 2025	1.23.12	End of Life
1.22	February 6, 2024	February 11, 2025	1.22.12	End of Life
1.21 (current page)	August 8, 2023	August 13, 2024	1.21.13	End of Life
1.20	February 1, 2023	February 6, 2024	1.20.14	End of Life
1.19	August 2, 2022	September 6, 2023	1.19.13	End of Life
1.18	March 15, 2022	February 1, 2023	1.18.10	End of Life
1.17	August 16, 2021	August 2, 2022	1.17.13	End of Life
1.16	February 16, 2021	March 15, 2022	1.16.15	End of Life
1.15	August 11, 2020	August 16, 2021	1.15.15	End of Life
1.14	February 25, 2020	February 16, 2021	1.14.15	End of Life
1.13	September 3, 2019	August 11, 2020	1.13.15	End of Life
1.12	February 25, 2019	February 25, 2020	1.12.17	End of Life
1.11	August 24, 2018	September 3, 2019	1.11.13	End of Life
1.10	February 16, 2018	February 25, 2019	1.10.8	End of Life

Frequently Asked Questions

When was Go 1.21 released?

Go 1.21 was released on August 8, 2023.

When does Go 1.21 reach end of life?

Go 1.21 reached end of life on August 13, 2024. It no longer receives security patches or bug fixes. You should upgrade to a supported version.

What is the latest patch version of Go 1.21?

The latest patch release is 1.21.13, released on August 6, 2024.

Should I still use Go 1.21?

No. Go 1.21 has reached end of life and no longer receives security updates. Running EOL software exposes your applications to unpatched vulnerabilities. You should plan an upgrade to a currently supported version.

Related Resources

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