0.66 Release Status

[NickGerleman]

Changelog: #8509 (comment)
Upstream issue: react-native-community/releases#246

The milestones below are based on those set for the upstream release and are subject to change.

Milestones

1. Upstream RC: Out
2. Release 0.66.0-preview.1: 9/6
3. Changes in 0.66-stable require triage: 9/13
4. Release target: ???

Important Issues

0.66 issues: https://github.com/microsoft/react-native-windows/issues?q=is%3Aopen+is%3Aissue+milestone%3A0.66

Blocking

• Update to Hermes 0.9 #8537

Checklist

Before Preview

• Draft GitHub release notes from commit log (NickGerleman)
• Snap Hermes-Windows release (mganandraj)
• Promote canary build to preview using wiki instructions (NickGerleman)
• Push build to 0.66-stable branch and publish (NickGerleman)
  • Enable CI schedule for 0.66-branch of CI pipeline
  • Update dashboard @ms with an entry for CI 0.66
  • Add release schedule for 0.66-stable of publish pipline
  • Update dashboard @microsoft with an entry for Publish 0.66
  • Create labels on GitHub for "Request, Approved, Backported to 0.66"
• Generate new diffs for upgrade-helper (NIckGerleman)
• Update GitHub release notes to use manually curated notes instead of a changelog (NickGerleman)
• Post release notes internally (NickGerleman)

---

After Preview

• Send mail to the team reminding of dates + restrictions (NickGerleman)
• Move most issues targeting 0.66 to 0.67 (chrisglein)
• Test updated gallery app (chiara)
• Do a pass on API Docs (???)
• Integrate patch/prerelease releases for React Native (NickGerleman)
• Modify CODEOWNERS to require changes go through @microsoft/react-native-windows-backport-triage (NickGerleman)
• Send reminder mail to the team about backport triage (NickGerleman)

---

Before Release

• Ensure any community typing changes happen (NickGerleman)
• Ensure doc issues are addressed (???)
• Promote latest build to legacy using wiki instructions (NickGerleman)
• Ensure all issues marked with "Blocking Label" are fixed (chrisglein)

---

Release

• Update preview release notes with any changes from cherry-picked PRs (NickGerleman)
• Update sample repos to new version (jonthysell), see upgrade procedure
• Update gallery to a new version (chiara)
• Promote preview build to latest using wiki instructions (NickGerleman)
• Update GitHub release notes to use manually curated notes instead of a changelog (NickGerleman)
• Flip docs site to 0.66 (???)
• Update the CI to tell the API doc generation tool to use the 0.66 prefix
• Send out internal release announcement (NickGerleman)
• Tweet/social (stmoy)

[NickGerleman]

Draft changelog:

We're excited to release our first preview build of react-native-windows 0.66! There have been many changes to both react-native-windows and react-native itself and we would love your feedback on anything that doesn't work as expected.

How to upgrade

You can view the differences between different versions of C++ applications using a special version of React Native Upgrade Helper.

Upgrade helper does not yet support C# projects or projects using experimental features. It is recommended to generate a new project using react-native-windows-init for projects not supported by Upgrade Helper.

What's New

• Fast Hermes in debug builds: We previously used debug builds of Hermes when you built your application in a debug configuration. We've heard feedback that this impacted usability, and now use an optimized JS engine regardless of whether your application is running in release or debug.

• Lower power consumption when using timers: Long running timers, such as those set by setInterval(), previously required RNW to do work every frame. We've fixed this, to let your application sleep until wake-up time.

• Better error UI: Your bundle failing to load previously showed a blank screen, requiring debugging your application to get actionable feedback. We now show a native redbox UI with the JavaScript exception.

• Windows 10 SDK version 10.0.19041.0: We now use the latest Windows SDK, included with Visual Studio. Note that you may still need to install previous SDKs to use community modules that have not yet updated.

• Hermes sampling profiler: In addition to heap space, you can now profile Hermes CPU usage via a sampling profiler.

• Improved responsiveness with expensive callbacks: We now coalesce events for layout and pointer movement to ensure your application stays responsive if JavaScript callbacks are expensive.

• More accessibility roles: We've added support for the togglebutton and header accessibility roles.

• Autolinking support for more community modules: React Native Windows has long-supported autolinking, but not all community modules for Windows were built to be compatible. Autolinking now has a heuristic to link any NPM dependencies that are likely Windows community modules.

• Native console redirection: You can now redirect the output of the JavaScript console object using the ReactInstanceSettings::NativeLogger property.

• JSValue XAML conversion helpers: We've added additional helpers to JSValueXaml.h to make it easier to write ViewManagers that serialize XAML types.

• Greater BackHandler control: You can now control whether to handle back events via the React Native BackHandler, or in native code, using QuirkSettings::SetBackHandlerKind.

• Bug-fixes and improvements: We've made many more fixes across the platform. Expect less crashes, more correct behavior, and more quality of life improvements for developers.

Breaking Changes

• Removal of Picker, DatePicker, PickerWindows: The various versions of Picker were previously deprecated as part of lean-core efforts. These components are removed in 0.66. The @react-native-community/datetimepicker and @react-native-picker/picker community modules can be used for the same functionality.

• UseExperimentalNuget configuration: Projects using the Microsoft.ReactNative NuGet package should now declare UseExperimentalNuget in their ExperimentalFeatures.props file instead of their vcxproj or csproj file.

[asklar]

• Updated to WinUI 2.6 (was that new for 66 or if it was in 65?)
• new "Loading" UI, now using WinUI 2.6's ProgressRing control

[NickGerleman]

WinUI 2.6 made it into 0.65. https://github.com/microsoft/react-native-windows/releases/tag/react-native-windows_v0.65.0