Impact Score: 5/10
Deno v0.20.0 — 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.
⚡ Executive Summary (TL;DR)
Deno v0.20.0. Source highlight: feat: Add Deno.hostname() (#3032)
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.
✨ New Features & Capabilities (6)
- feat: Add Deno.hostname() (#3032)
- feat: Add support for passing a key to Deno.env() (#2952)
- feat: JSX Support (#3038)
- feat: window.onunload (#3023)
- feat: test runner v2 (denoland/deno_std#604)
- feat: wss support with dialTLS (denoland/deno_std#615)
🔧 Bug Fixes & Patches (6)
- feat: Replace Isolate::set_dispatch with Isolate::register_op (#3002, #3039,
- fix: Async compiler processing (#3043)
- fix: Implement ignoreBOM option of UTF8Decoder in text_encoding (#3040)
- fix: Support top-level-await in TypeScript (#3024)
- fix: iterators on UrlSearchParams (#3044)
- fix: listenDefaults/dialDefaults may be overriden in some cases (#3027)
📄 View Raw Release Notes (Original Developer Log)
### Changes
In deno:
- feat: Add Deno.hostname() (#3032)
- feat: Add support for passing a key to Deno.env() (#2952)
- feat: JSX Support (#3038)
- feat: Replace Isolate::set_dispatch with Isolate::register_op (#3002, #3039,
#3041)
- feat: window.onunload (#3023)
- fix: Async compiler processing (#3043)
- fix: Implement ignoreBOM option of UTF8Decoder in text_encoding (#3040)
- fix: Support top-level-await in TypeScript (#3024)
- fix: iterators on UrlSearchParams (#3044)
- fix: listenDefaults/dialDefaults may be overriden in some cases (#3027)
- upgrade: V8 to 7.9.218 (#3067)
- upgrade: rust to 1.38.0 (#3030)
- chore: Migrate CI to github actions (#3052, #3056, #3049, #3071, #3076, #3070,
#3066, #3061, #3010)
- chore: Remove deno_cli_snapshots crate. Move //js to //cli/js (#3064)
- chore: use xeval from deno_std (#3058)
In deno_std:
- feat: test runner v2 (denoland/deno_std#604)
- feat: wss support with dialTLS (denoland/deno_std#615)
- fix(ws): mask must not be set by default for server (denoland/deno_std#616)
- fix: Implement expandGlob() and expandGlobSync() (denoland/deno_std#617)
- upgrade: eslint and @typescript-eslint (denoland/deno_std#621)
### Install / Upgrade
**With Shell:**
```sh
curl -fsSL https://deno.land/x/install/install.sh | sh -s v0.20.0
```
**With PowerShell:**
```powershell
iwr https://deno.land/x/install/install.ps1 -useb -outf install.ps1; .\install.ps1 v0.20.0
```