From 2a4e0fbaea5b8bc266b7af395fb97790551adca2 Mon Sep 17 00:00:00 2001
From: Anna Garcia <anna.g@posthog.com>
Date: Mon, 5 Oct 2026 12:25:31 -0400
Subject: [PATCH 1/4] feat(react-native): send $react_native_version with every
 event

Reads Platform.constants.reactNativeVersion so we can see which React Native versions SDK users run before choosing support floors.
---
 .changeset/react-native-version-property.md   |  5 +++
 packages/react-native/src/native-deps.tsx     |  7 ++-
 packages/react-native/src/types.ts            |  2 +
 packages/react-native/src/utils.ts            | 17 +++++++
 .../test/react-native-version.spec.ts         | 45 +++++++++++++++++++
 5 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/react-native-version-property.md
 create mode 100644 packages/react-native/test/react-native-version.spec.ts

diff --git a/.changeset/react-native-version-property.md b/.changeset/react-native-version-property.md
new file mode 100644
index 0000000000..9672d929ec
--- /dev/null
+++ b/.changeset/react-native-version-property.md
@@ -0,0 +1,5 @@
+---
+'posthog-react-native': minor
+---
+
+Add `$react_native_version` (for example `0.79.6`) to every captured event
diff --git a/packages/react-native/src/native-deps.tsx b/packages/react-native/src/native-deps.tsx
index 8cc1b4af34..67e295837c 100644
--- a/packages/react-native/src/native-deps.tsx
+++ b/packages/react-native/src/native-deps.tsx
@@ -1,5 +1,5 @@
 import { OptionalAsyncStorage } from './optional/OptionalAsyncStorage'
-import { GLOBAL_OBJ, getPlatformOS, isMacOS, isWeb, isWindows } from './utils'
+import { GLOBAL_OBJ, getPlatformOS, getReactNativeVersion, isMacOS, isWeb, isWindows } from './utils'
 import { OptionalExpoApplication } from './optional/OptionalExpoApplication'
 import { OptionalExpoDevice } from './optional/OptionalExpoDevice'
 import { OptionalExpoFileSystem } from './optional/OptionalExpoFileSystem'
@@ -39,6 +39,11 @@ export const getAppProperties = (): PostHogCustomAppProperties => {
     $device_type: currentDeviceType,
   }
 
+  const reactNativeVersion = getReactNativeVersion()
+  if (reactNativeVersion) {
+    properties.$react_native_version = reactNativeVersion
+  }
+
   if (OptionalExpoApplication) {
     properties.$app_build = OptionalExpoApplication.nativeBuildVersion
     properties.$app_name = OptionalExpoApplication.applicationName
diff --git a/packages/react-native/src/types.ts b/packages/react-native/src/types.ts
index cc22cdcfe2..4029443153 100644
--- a/packages/react-native/src/types.ts
+++ b/packages/react-native/src/types.ts
@@ -154,6 +154,8 @@ export interface PostHogCustomAppProperties {
   $timezone?: string | null
   /** Whether the app is running on an emulator/simulator */
   $is_emulator?: boolean | null
+  /** React Native version like "0.79.6" */
+  $react_native_version?: string | null
 }
 
 export type PostHogSessionReplayConfig = {
diff --git a/packages/react-native/src/utils.ts b/packages/react-native/src/utils.ts
index acd597046f..43f7f5daa1 100644
--- a/packages/react-native/src/utils.ts
+++ b/packages/react-native/src/utils.ts
@@ -51,3 +51,20 @@ export function isWindows(): boolean {
 }
 
 export const isHermes = () => !!GLOBAL_OBJ.HermesInternal
+
+type ReactNativeVersion = { major: number; minor: number; patch: number; prerelease?: number | string | null }
+
+/** React Native version like "0.79.6" or "0.80.0-rc.2", or undefined where Platform.constants doesn't report it (e.g. web) */
+export function getReactNativeVersion(): string | undefined {
+  try {
+    const version = (Platform as { constants?: { reactNativeVersion?: ReactNativeVersion } }).constants
+      ?.reactNativeVersion
+    if (!version) {
+      return undefined
+    }
+    const { major, minor, patch, prerelease } = version
+    return `${major}.${minor}.${patch}${prerelease != null ? `-${prerelease}` : ''}`
+  } catch {
+    return undefined
+  }
+}
diff --git a/packages/react-native/test/react-native-version.spec.ts b/packages/react-native/test/react-native-version.spec.ts
new file mode 100644
index 0000000000..d9416e9cf6
--- /dev/null
+++ b/packages/react-native/test/react-native-version.spec.ts
@@ -0,0 +1,45 @@
+import { Platform } from 'react-native'
+import { PostHog } from '../src'
+import { getReactNativeVersion } from '../src/utils'
+
+const platform = Platform as typeof Platform & { constants?: unknown }
+
+describe('$react_native_version', () => {
+  afterEach(() => {
+    delete platform.constants
+  })
+
+  it('formats Platform.constants.reactNativeVersion', () => {
+    platform.constants = { reactNativeVersion: { major: 0, minor: 79, patch: 6, prerelease: null } }
+    expect(getReactNativeVersion()).toBe('0.79.6')
+  })
+
+  it('appends the prerelease tag', () => {
+    platform.constants = { reactNativeVersion: { major: 0, minor: 80, patch: 0, prerelease: 'rc.2' } }
+    expect(getReactNativeVersion()).toBe('0.80.0-rc.2')
+  })
+
+  it('is undefined when the platform does not report a version', () => {
+    platform.constants = {}
+    expect(getReactNativeVersion()).toBeUndefined()
+  })
+
+  it('is sent with every event', async () => {
+    platform.constants = { reactNativeVersion: { major: 0, minor: 79, patch: 6 } }
+    const posthog = new PostHog('test-token', { flushInterval: 0 })
+    await posthog.ready()
+
+    expect(posthog.getCommonEventProperties().$react_native_version).toBe('0.79.6')
+
+    await posthog.shutdown()
+  })
+
+  it('is omitted when the platform does not report a version', async () => {
+    const posthog = new PostHog('test-token', { flushInterval: 0 })
+    await posthog.ready()
+
+    expect(posthog.getCommonEventProperties()).not.toHaveProperty('$react_native_version')
+
+    await posthog.shutdown()
+  })
+})

From 75578fbdfba7ce1845911def414bf8430c979a61 Mon Sep 17 00:00:00 2001
From: Anna Garcia <anna.g@posthog.com>
Date: Mon, 5 Oct 2026 12:32:21 -0400
Subject: [PATCH 2/4] chore(react-native): regenerate references and scope
 $react_native_version to JS events

---
 .changeset/react-native-version-property.md                  | 2 +-
 .../references/posthog-react-native-references-latest.json   | 5 +++++
 packages/react-native/src/types.ts                           | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/.changeset/react-native-version-property.md b/.changeset/react-native-version-property.md
index 9672d929ec..4354e05674 100644
--- a/.changeset/react-native-version-property.md
+++ b/.changeset/react-native-version-property.md
@@ -2,4 +2,4 @@
 'posthog-react-native': minor
 ---
 
-Add `$react_native_version` (for example `0.79.6`) to every captured event
+Add `$react_native_version` (for example `0.79.6`) to events captured from JavaScript
diff --git a/packages/react-native/references/posthog-react-native-references-latest.json b/packages/react-native/references/posthog-react-native-references-latest.json
index 24bb425336..39aac79625 100644
--- a/packages/react-native/references/posthog-react-native-references-latest.json
+++ b/packages/react-native/references/posthog-react-native-references-latest.json
@@ -3347,6 +3347,11 @@
           "type": "string | null",
           "name": "$os_version"
         },
+        {
+          "description": "React Native version like \"0.79.6\". Set on events captured from JavaScript, not on events the native SDKs capture",
+          "type": "string | null",
+          "name": "$react_native_version"
+        },
         {
           "description": "Timezone of the device like \"Europe/Berlin\"",
           "type": "string | null",
diff --git a/packages/react-native/src/types.ts b/packages/react-native/src/types.ts
index 4029443153..fe5dbe266e 100644
--- a/packages/react-native/src/types.ts
+++ b/packages/react-native/src/types.ts
@@ -154,7 +154,7 @@ export interface PostHogCustomAppProperties {
   $timezone?: string | null
   /** Whether the app is running on an emulator/simulator */
   $is_emulator?: boolean | null
-  /** React Native version like "0.79.6" */
+  /** React Native version like "0.79.6". Set on events captured from JavaScript, not on events the native SDKs capture */
   $react_native_version?: string | null
 }
 

From 0c2f1eac9539a0be84c2044cc663b0568c1d991d Mon Sep 17 00:00:00 2001
From: Anna Garcia <anna.g@posthog.com>
Date: Mon, 5 Oct 2026 12:35:33 -0400
Subject: [PATCH 3/4] fix(react-native): ignore malformed RN version constants
 and cover the throwing path

---
 .../posthog-react-native-references-latest.json   |  2 +-
 packages/react-native/src/types.ts                |  2 +-
 packages/react-native/src/utils.ts                |  2 +-
 .../test/react-native-version.spec.ts             | 15 +++++++++++++++
 4 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/packages/react-native/references/posthog-react-native-references-latest.json b/packages/react-native/references/posthog-react-native-references-latest.json
index 39aac79625..8ec178bd13 100644
--- a/packages/react-native/references/posthog-react-native-references-latest.json
+++ b/packages/react-native/references/posthog-react-native-references-latest.json
@@ -3348,7 +3348,7 @@
           "name": "$os_version"
         },
         {
-          "description": "React Native version like \"0.79.6\". Set on events captured from JavaScript, not on events the native SDKs capture",
+          "description": "React Native version like \"0.79.6\"",
           "type": "string | null",
           "name": "$react_native_version"
         },
diff --git a/packages/react-native/src/types.ts b/packages/react-native/src/types.ts
index fe5dbe266e..4029443153 100644
--- a/packages/react-native/src/types.ts
+++ b/packages/react-native/src/types.ts
@@ -154,7 +154,7 @@ export interface PostHogCustomAppProperties {
   $timezone?: string | null
   /** Whether the app is running on an emulator/simulator */
   $is_emulator?: boolean | null
-  /** React Native version like "0.79.6". Set on events captured from JavaScript, not on events the native SDKs capture */
+  /** React Native version like "0.79.6" */
   $react_native_version?: string | null
 }
 
diff --git a/packages/react-native/src/utils.ts b/packages/react-native/src/utils.ts
index 43f7f5daa1..91e071f107 100644
--- a/packages/react-native/src/utils.ts
+++ b/packages/react-native/src/utils.ts
@@ -59,7 +59,7 @@ export function getReactNativeVersion(): string | undefined {
   try {
     const version = (Platform as { constants?: { reactNativeVersion?: ReactNativeVersion } }).constants
       ?.reactNativeVersion
-    if (!version) {
+    if (!version || typeof version.major !== 'number') {
       return undefined
     }
     const { major, minor, patch, prerelease } = version
diff --git a/packages/react-native/test/react-native-version.spec.ts b/packages/react-native/test/react-native-version.spec.ts
index d9416e9cf6..ab4b81b1d9 100644
--- a/packages/react-native/test/react-native-version.spec.ts
+++ b/packages/react-native/test/react-native-version.spec.ts
@@ -24,6 +24,21 @@ describe('$react_native_version', () => {
     expect(getReactNativeVersion()).toBeUndefined()
   })
 
+  it('is undefined when the version object has no numeric fields', () => {
+    platform.constants = { reactNativeVersion: {} }
+    expect(getReactNativeVersion()).toBeUndefined()
+  })
+
+  it('is undefined when reading the constants throws', () => {
+    Object.defineProperty(platform, 'constants', {
+      configurable: true,
+      get: () => {
+        throw new Error('getConstants failed')
+      },
+    })
+    expect(getReactNativeVersion()).toBeUndefined()
+  })
+
   it('is sent with every event', async () => {
     platform.constants = { reactNativeVersion: { major: 0, minor: 79, patch: 6 } }
     const posthog = new PostHog('test-token', { flushInterval: 0 })

From f2c8870f6dd4e2d18aa2b6898fc421e1cd710067 Mon Sep 17 00:00:00 2001
From: Anna Garcia <anna.g@posthog.com>
Date: Mon, 5 Oct 2026 12:50:39 -0400
Subject: [PATCH 4/4] fix(core): keep $react_native_version on minimal
 $feature_flag_called events

---
 .changeset/core-flag-called-react-native-version.md     | 5 +++++
 packages/core/src/featureFlagUtils.ts                   | 2 ++
 packages/react-native/test/react-native-version.spec.ts | 7 +++++++
 3 files changed, 14 insertions(+)
 create mode 100644 .changeset/core-flag-called-react-native-version.md

diff --git a/.changeset/core-flag-called-react-native-version.md b/.changeset/core-flag-called-react-native-version.md
new file mode 100644
index 0000000000..2e6897b160
--- /dev/null
+++ b/.changeset/core-flag-called-react-native-version.md
@@ -0,0 +1,5 @@
+---
+'@posthog/core': patch
+---
+
+Keep `$react_native_version` on minimal `$feature_flag_called` events
diff --git a/packages/core/src/featureFlagUtils.ts b/packages/core/src/featureFlagUtils.ts
index ef0f4bf5eb..2e3fa33f92 100644
--- a/packages/core/src/featureFlagUtils.ts
+++ b/packages/core/src/featureFlagUtils.ts
@@ -252,6 +252,8 @@ export const MINIMAL_FLAG_CALLED_EVENT_PROPERTIES: readonly string[] = [
   '$lib_version',
   '$device_id',
   '$is_server',
+  // Runtime identity, kept for runtime breakdowns of flag calls
+  '$react_native_version',
 ]
 
 /**
diff --git a/packages/react-native/test/react-native-version.spec.ts b/packages/react-native/test/react-native-version.spec.ts
index ab4b81b1d9..756be09e8f 100644
--- a/packages/react-native/test/react-native-version.spec.ts
+++ b/packages/react-native/test/react-native-version.spec.ts
@@ -1,4 +1,5 @@
 import { Platform } from 'react-native'
+import { minimizeFlagCalledEventProperties } from '@posthog/core'
 import { PostHog } from '../src'
 import { getReactNativeVersion } from '../src/utils'
 
@@ -49,6 +50,12 @@ describe('$react_native_version', () => {
     await posthog.shutdown()
   })
 
+  it('survives minimal $feature_flag_called events', () => {
+    expect(minimizeFlagCalledEventProperties({ $react_native_version: '0.79.6', custom: 'dropped' })).toEqual({
+      $react_native_version: '0.79.6',
+    })
+  })
+
   it('is omitted when the platform does not report a version', async () => {
     const posthog = new PostHog('test-token', { flushInterval: 0 })
     await posthog.ready()