Deno v0.39.0 — Release Notes & Engineering Impact

Source available — automated, not human-reviewed

Component: deno · Channel: stable. Automated analysis, not a compatibility certification. How this works.

Analysis updated: 2026-11-01.

Breaking-change evidence from the source

- BREAKING CHANGE: Move encode, decode helpers to /std/encoding/utf8.ts, delete /std/strings/ (#4565)
- BREAKING CHANGE: Remove /std/media_types (#4594)
- BREAKING CHANGE: Remove old release files (#4545)
- BREAKING CHANGE: Remove std/strings/pad.ts because String.prototype.padStart exists (#4564)

Read the original context ↗

Source flags breaking changes — review applicability

📄 .MD

✨ Features 6 🔧 Bug Fixes 6 ⚠️ Breaking & Deprecations 4

⚡ Executive Summary (TL;DR)

Deno v0.39.0. Source highlight: BREAKING CHANGE: Move encode, decode helpers to /std/encoding/utf8.ts, delete /std/strings/ (#4565)

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Who Does This Impact? (Role-Based Analysis)

💻 Software Engineers & Devs

Check the source notes against the package and APIs you use before upgrading.

📊 Product & Engineering Leads

Use the documented changes to assess relevance to your product; release frequency alone is not a quality measure.

⚙️ DevOps & Security

Verify the target version, runtime requirements and rollback procedure in the official documentation.

⚠️ Breaking Changes & Deprecations (4)

- BREAKING CHANGE: Move encode, decode helpers to /std/encoding/utf8.ts, delete /std/strings/ (#4565)
- BREAKING CHANGE: Remove /std/media_types (#4594)
- BREAKING CHANGE: Remove old release files (#4545)
- BREAKING CHANGE: Remove std/strings/pad.ts because String.prototype.padStart exists (#4564)

✨ New Features & Capabilities (6)

feat: Add common to std/path (#4527)
feat: Added colors to doc output (#4518)
feat: Expose global state publicly (#4572)
feat: Make inspector more robust, add --inspect-brk support (#4552)
feat: Publish deno types on release (#4583)
feat: Support dynamic import in bundles. (#4561)

🔧 Bug Fixes & Patches (6)

fix(#4550): setCookie should append cookies (#4558)
fix(#4554): use --inspect in repl & eval (#4562)
fix(deno doc): handle 'declare' (#4573)
fix(deno doc): parse super-class names (#4595)
fix(deno doc): parse the "implements" clause of a class def (#4604)
fix(file_server): serve appropriate content-type header (#4555)

📄 View Raw Release Notes (Original Developer Log)

### Changes - BREAKING CHANGE: Move encode, decode helpers to /std/encoding/utf8.ts, delete /std/strings/ (#4565) - BREAKING CHANGE: Remove /std/media_types (#4594) - BREAKING CHANGE: Remove old release files (#4545) - BREAKING CHANGE: Remove std/strings/pad.ts because String.prototype.padStart exists (#4564) - feat: Add common to std/path (#4527) - feat: Added colors to doc output (#4518) - feat: Expose global state publicly (#4572) - feat: Make inspector more robust, add --inspect-brk support (#4552) - feat: Publish deno types on release (#4583) - feat: Support dynamic import in bundles. (#4561) - feat: deno test --filter (#4570) - feat: improve console.log serialization (#4524, #4472) - fix(#4550): setCookie should append cookies (#4558) - fix(#4554): use --inspect in repl & eval (#4562) - fix(deno doc): handle 'declare' (#4573) - fix(deno doc): parse super-class names (#4595) - fix(deno doc): parse the "implements" clause of a class def (#4604) - fix(file_server): serve appropriate content-type header (#4555) - fix(inspector): proper error message on port collision (#4514) - fix: Add check to fail the benchmark test on server error (#4519) - fix: Properly handle invalid utf8 in paths (#4609) - fix: async ops sanitizer false positives in timers (#4602) - fix: invalid blob type (#4536) - fix: make Worker.poll private (#4603) - fix: remove `Send` trait requirement from the `Resource` trait (#4585) - refactor(testing): Reduce testing interfaces (#4451) - upgrade: dprint to 0.9.10 (#4601) - upgrade: rusty_v8 v0.3.10 (#4576) ### Install / Upgrade **Using Deno:** ```sh deno upgrade ``` **With Shell:** ```sh curl -fsSL https://deno.land/x/install/install.sh | sh -s v0.39.0 ``` **With PowerShell:** ```powershell iwr https://deno.land/x/install/install.ps1 -useb -outf install.ps1; .\install.ps1 v0.39.0 ```

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