diff --git a/packages/react-dom/src/events/ReactDOMEventReplaying.js b/packages/react-dom/src/events/ReactDOMEventReplaying.js
index 2068259243032..9251da4eaa637 100644
--- a/packages/react-dom/src/events/ReactDOMEventReplaying.js
+++ b/packages/react-dom/src/events/ReactDOMEventReplaying.js
@@ -20,7 +20,6 @@ import type {
 import {
   enableDeprecatedFlareAPI,
   enableSelectiveHydration,
-  enableModernEventSystem,
 } from 'shared/ReactFeatureFlags';
 import {
   unstable_runWithPriority as runWithPriority,
diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
index f97ea6392009f..9e9ec4f75ad7c 100644
--- a/packages/shared/ReactFeatureFlags.js
+++ b/packages/shared/ReactFeatureFlags.js
@@ -111,9 +111,6 @@ export const disableModulePatternComponents = false;
 // We should remove this flag once the above flag becomes enabled
 export const warnUnstableRenderSubtreeIntoContainer = false;
 
-// Modern event system where events get registered at roots
-export const enableModernEventSystem = false;
-
 // Support legacy Primer support on internal FB www
 export const enableLegacyFBSupport = false;
 
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb.js b/packages/shared/forks/ReactFeatureFlags.native-fb.js
index 48005e6e1d1cf..cbb47f8cf4b73 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb.js
@@ -39,7 +39,6 @@ export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const disableModulePatternComponents = false;
 export const warnUnstableRenderSubtreeIntoContainer = false;
-export const enableModernEventSystem = false;
 export const warnAboutSpreadingKeyToJSX = false;
 export const enableComponentStackLocations = false;
 export const enableLegacyFBSupport = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
index 9bf701bc1f12f..779e3379aac4b 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-oss.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -38,7 +38,6 @@ export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const disableModulePatternComponents = false;
 export const warnUnstableRenderSubtreeIntoContainer = false;
-export const enableModernEventSystem = false;
 export const warnAboutSpreadingKeyToJSX = false;
 export const enableComponentStackLocations = false;
 export const enableLegacyFBSupport = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
index 7e3213a16b1f1..2837ff17dad5f 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
@@ -38,7 +38,6 @@ export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const disableModulePatternComponents = false;
 export const warnUnstableRenderSubtreeIntoContainer = false;
-export const enableModernEventSystem = false;
 export const warnAboutSpreadingKeyToJSX = false;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
index 9b550dd3e7cf3..5e036a4a17257 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
@@ -38,7 +38,6 @@ export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const disableModulePatternComponents = true;
 export const warnUnstableRenderSubtreeIntoContainer = false;
-export const enableModernEventSystem = false;
 export const warnAboutSpreadingKeyToJSX = false;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.testing.js b/packages/shared/forks/ReactFeatureFlags.testing.js
index bf87ee4a5f691..8f4930fedfd6d 100644
--- a/packages/shared/forks/ReactFeatureFlags.testing.js
+++ b/packages/shared/forks/ReactFeatureFlags.testing.js
@@ -38,7 +38,6 @@ export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const disableModulePatternComponents = false;
 export const warnUnstableRenderSubtreeIntoContainer = false;
-export const enableModernEventSystem = false;
 export const warnAboutSpreadingKeyToJSX = false;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.testing.www.js b/packages/shared/forks/ReactFeatureFlags.testing.www.js
index 2caf1e60792e3..3f47f5a8f4acf 100644
--- a/packages/shared/forks/ReactFeatureFlags.testing.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.testing.www.js
@@ -27,7 +27,7 @@ export const enableSchedulerDebugging = false;
 export const enableDeprecatedFlareAPI = true;
 export const enableFundamentalAPI = false;
 export const enableScopeAPI = true;
-export const enableCreateEventHandleAPI = false;
+export const enableCreateEventHandleAPI = true;
 export const warnAboutUnmockedScheduler = true;
 export const enableSuspenseCallback = true;
 export const warnAboutDefaultPropsOnFunctionComponents = false;
@@ -38,7 +38,6 @@ export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = __EXPERIMENTAL__;
 export const disableModulePatternComponents = true;
 export const warnUnstableRenderSubtreeIntoContainer = false;
-export const enableModernEventSystem = false;
 export const warnAboutSpreadingKeyToJSX = false;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = !__EXPERIMENTAL__;
diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
index a3c26a6bdcaf8..15592c39095f5 100644
--- a/packages/shared/forks/ReactFeatureFlags.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -71,8 +71,6 @@ export const disableTextareaChildren = __EXPERIMENTAL__;
 
 export const warnUnstableRenderSubtreeIntoContainer = false;
 
-export const enableModernEventSystem = true;
-
 // Enable forked reconciler. Piggy-backing on the "variant" global so that we
 // don't have to add another test dimension. The build system will compile this
 // to the correct value.