diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 768a79d68d..99878d0eb3 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -57,13 +57,13 @@
 *   Text:
     *   Parse SSA/ASS font size in `Style:` lines
         ([#8435](https://github.com/google/ExoPlayer/issues/8435)).
-*   VP9 extension: Update to use NDK r22
+*   VP9 extension: Update to use NDK r21
     ([#8581](https://github.com/google/ExoPlayer/issues/8581)).
-*   FLAC extension: Update to use NDK r22
+*   FLAC extension: Update to use NDK r21
     ([#8581](https://github.com/google/ExoPlayer/issues/8581)).
-*   Opus extension: Update to use NDK r22
+*   Opus extension: Update to use NDK r21
     ([#8581](https://github.com/google/ExoPlayer/issues/8581)).
-*   FFmpeg extension: Update to use NDK r22
+*   FFmpeg extension: Update to use NDK r21
     ([#8581](https://github.com/google/ExoPlayer/issues/8581)).
 *   MediaSession extension: Remove dependency to core module and rely on common
     only. The `TimelineQueueEditor` uses a new `MediaDescriptionConverter` for
diff --git a/extensions/ffmpeg/README.md b/extensions/ffmpeg/README.md
index 68eafd2926..da2fa40141 100644
--- a/extensions/ffmpeg/README.md
+++ b/extensions/ffmpeg/README.md
@@ -30,7 +30,7 @@ FFMPEG_EXT_PATH="${EXOPLAYER_ROOT}/extensions/ffmpeg/src/main"
 ```
 
 * Download the [Android NDK][] and set its location in a shell variable.
-  This build configuration has been tested on NDK r22.
+  This build configuration has been tested on NDK r21.
 
 ```
 NDK_PATH="<path to Android NDK>"
diff --git a/extensions/flac/README.md b/extensions/flac/README.md
index 5b98e33364..074daca71e 100644
--- a/extensions/flac/README.md
+++ b/extensions/flac/README.md
@@ -29,7 +29,7 @@ FLAC_EXT_PATH="${EXOPLAYER_ROOT}/extensions/flac/src/main"
 ```
 
 * Download the [Android NDK][] and set its location in an environment variable.
-  This build configuration has been tested on NDK r22.
+  This build configuration has been tested on NDK r21.
 
 ```
 NDK_PATH="<path to Android NDK>"
diff --git a/extensions/opus/README.md b/extensions/opus/README.md
index 6a68a1946b..4daff54abf 100644
--- a/extensions/opus/README.md
+++ b/extensions/opus/README.md
@@ -29,7 +29,7 @@ OPUS_EXT_PATH="${EXOPLAYER_ROOT}/extensions/opus/src/main"
 ```
 
 * Download the [Android NDK][] and set its location in an environment variable.
-  This build configuration has been tested on NDK r22.
+  This build configuration has been tested on NDK r21.
 
 ```
 NDK_PATH="<path to Android NDK>"
diff --git a/extensions/vp9/README.md b/extensions/vp9/README.md
index 3abf72758d..30b7a252d0 100644
--- a/extensions/vp9/README.md
+++ b/extensions/vp9/README.md
@@ -29,7 +29,7 @@ VP9_EXT_PATH="${EXOPLAYER_ROOT}/extensions/vp9/src/main"
 ```
 
 * Download the [Android NDK][] and set its location in an environment variable.
-  This build configuration has been tested on NDK r22.
+  This build configuration has been tested on NDK r21.
 
 ```
 NDK_PATH="<path to Android NDK>"