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Upgrade Insecure Requests

- CR

Declare that browsers should transparently upgrade HTTP resources on a website to HTTPS.

Chrome

  1. ❌ 4 - 42: Not supported
  2. ✅ 43 - 137: Supported
  3. ✅ 138: Supported
  4. ✅ 139 - 141: Supported

Edge

  1. ❌ 12 - 16: Not supported
  2. ✅ 17 - 137: Supported
  3. ✅ 138: Supported

Safari

  1. ❌ 3.1 - 10: Not supported
  2. ✅ 10.1 - 18.4: Supported
  3. ✅ 18.5: Supported
  4. ✅ 26.0 - TP: Supported

Firefox

  1. ❌ 2 - 41: Not supported
  2. ✅ 42 - 139: Supported
  3. ✅ 140: Supported
  4. ✅ 141 - 143: Supported

Opera

  1. ❌ 9 - 29: Not supported
  2. ✅ 30 - 116: Supported
  3. ✅ 117: Supported

IE

  1. ❌ 5.5 - 10: Not supported
  2. ❌ 11: Not supported

Chrome for Android

  1. ✅ 138: Supported

Safari on iOS

  1. ❌ 3.2 - 10.2: Not supported
  2. ✅ 10.3 - 18.4: Supported
  3. ✅ 18.5: Supported
  4. ✅ 26.0: Supported

Samsung Internet

  1. ✅ 4 - 27: Supported
  2. ✅ 28: Supported

Opera Mini

  1. ❌ all: Not supported

Opera Mobile

  1. ❌ 10 - 12.1: Not supported
  2. ✅ 80: Supported

UC Browser for Android

  1. ✅ 15.5: Supported

Android Browser

  1. ❌ 2.1 - 4.4.4: Not supported
  2. ✅ 138: Supported

Firefox for Android

  1. ✅ 140: Supported

QQ Browser

  1. ✅ 14.9: Supported

Baidu Browser

  1. ✅ 13.52: Supported

KaiOS Browser

  1. ✅ 2.5: Supported
  2. ✅ 3: Supported

The HTTP header is Content-Security-Policy: upgrade-insecure-requests. Alternatively, the HTML tag is <meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">.

Resources:
WebKit feature request bug
MDN Web Docs - Upgrade Insecure Requests
Demo Website