diff --git a/extensions/vp9/proguard-rules.txt b/extensions/vp9/proguard-rules.txt
index c3cd063680..6e473eb21e 100644
--- a/extensions/vp9/proguard-rules.txt
+++ b/extensions/vp9/proguard-rules.txt
@@ -9,3 +9,9 @@
 -keep class com.google.android.exoplayer2.video.VideoDecoderOutputBuffer {
     *;
 }
+
+# The deprecated VpxOutputBuffer might be used by old binary versions. Remove
+# once VpxOutputBuffer is removed.
+-keep class com.google.android.exoplayer2.ext.vp9.VpxOutputBuffer {
+    *;
+}
diff --git a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxOutputBuffer.java b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxOutputBuffer.java
index 99f35217fc..6d36164d1d 100644
--- a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxOutputBuffer.java
+++ b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxOutputBuffer.java
@@ -18,7 +18,8 @@ package com.google.android.exoplayer2.ext.vp9;
 import com.google.android.exoplayer2.video.VideoDecoderOutputBuffer;
 
 // TODO(b/139174707): Delete this class once binaries in WVVp9OpusPlaybackTest are updated to depend
-// on VideoDecoderOutputBuffer. Also mark VideoDecoderOutputBuffer as final.
+// on VideoDecoderOutputBuffer. Also mark VideoDecoderOutputBuffer as final and remove proguard
+// config for VpxOutputBuffer.
 /**
  * Video output buffer, populated by {@link VpxDecoder}.
  *