feat(js): Add v10 migration guide (#14506)

> [!IMPORTANT] 
> This is opened as a draft PR to ensure it's only merged after we
release v10. Reviews can already happen.

---------

Co-authored-by: Sigrid Huemer <[email protected]>
Co-authored-by: Lukas Stracke <[email protected]>
Co-authored-by: Abhijeet Prasad <[email protected]>

Author: 4 people

docs/platforms/javascript/common/migration/v9-to-v10.mdx

@@ -0,0 +1,99 @@
+---
+title: Migrate from 9.x to 10.x
+sidebar_order: 8880
+description: "Learn about migrating from Sentry JavaScript SDK 9.x to 10.x"
+notSupported:
+  - javascript.capacitor
+  - javascript.cordova
+  - javascript.electron
+---
+
+<PlatformSection supported={["javascript"]}>
+<Alert title="Using a framework?" level="info">
+
+Make sure to select your framework in the dropdown in the top left corner of the page.
+
+</Alert>
+</PlatformSection>
+
+Version 10 of the Sentry JavaScript SDK primarily focuses on upgrading underlying OpenTelemetry dependencies to v2 with minimal breaking changes.
+
+Version 10 of the SDK is compatible with Sentry self-hosted versions 24.4.2 or higher (unchanged from v9).
+Lower versions may continue to work, but may not support all features.
+
+## Version Support Changes:
+
+Version 10 of the Sentry SDK has new compatibility ranges for runtimes and frameworks.
+
+### Node.js
+
+All OpenTelemetry dependencies have been bumped to `2.x.x` / `0.20x.x` respectively, and all OpenTelemetry instrumentations have been upgraded to their latest version.
+
+If you cannot run with OpenTelemetry v2 versions, consider either staying on Version 9 of our SDKs or using [@sentry/node-core](https://www.npmjs.com/package/@sentry/node-core) instead, which ships with widened OpenTelemetry peer dependencies.
+
+### AWS Lambda Layer Changes
+
+A new AWS Lambda Layer for version 10 will be published as `SentryNodeServerlessSDKv10`.
+
+Updates and fixes for version 9 will be published as `SentryNodeServerlessSDKv9`.
+
+<PlatformCategorySection supported={['browser']}>
+
+## Removed FID Web Vital reporting
+
+**The SDKs no longer report the First Input Delay (FID) web vital**.
+
+This was done because FID has been replaced by Interaction to Next Paint (INP) and is therefore no longer relevant for assessing and tracking a website's performance.
+For reference, FID has long been deprecated by Google's official `web-vitals` library and was eventually removed in version `5.0.0`.
+Sentry now follows Google's lead by also removing it.
+
+The removal entails **no breaking API changes**. However, in rare cases, you might need to adjust some of your Sentry SDK and product setup:
+
+- Remove any logic in `beforeSend` or other filtering/event processing logic that depends on FID or replace it with INP logic.
+- If you set up Sentry Alerts that depend on FID, be aware that these could trigger once you upgrade the SDK, due to a lack of new values.
+  To replace them, adjust your alerts (or dashboards) to use INP.
+
+## Removed `_experiments.autoFlushOnFeedback` for Session Replays
+
+The `_experiments.autoFlushOnFeedback` option was removed and is now the default behavior.
+
+</PlatformCategorySection>
+
+## Removed APIs
+
+The changes outlined in this section detail deprecated APIs that are now removed.
+
+- `BaseClient` was removed, use `Client` as a direct replacement.
+- `hasTracingEnabled` was removed, use `hasSpansEnabled` as a direct replacement.
+- The internal `logger` and type `Logger` exports in `@sentry/core` were removed, use `debug` and type `SentryDebugLogger` instead. This does not affect the `logger` export used for [Sentry Logging](https://docs.sentry.io/product/explore/logs/getting-started/)
+- The `_experiments.enableLogs` and `_experiments.beforeSendLog` options were removed, use the top-level `enableLogs` and `beforeSendLog` options instead.
+
+```js
+// before
+Sentry.init({
+  _experiments: {
+    enableLogs: true,
+    beforeSendLog: (log) => {
+      return log;
+    },
+  },
+});
+
+// after
+Sentry.init({
+  enableLogs: true,
+  beforeSendLog: (log) => {
+    return log;
+  },
+});
+```
+
+## Version Support Timeline
+
+Version support timelines can be stressful for everybody using the SDK, so we won't be defining one.
+Instead, we will be applying bug fixes and features to older versions as long as there is demand.
+
+Additionally, we hold ourselves accountable for any security issues, meaning that if any vulnerabilities are found, we will, in almost all, cases backport them.
+
+Note, that backporting decisions are made on a case-by-case basis.
+If you need a fix or feature in a previous version of the SDK, please reach out via a [GitHub Issue](https://github.com/getsentry/sentry-javascript/issues).