diff --git a/docs/samples/explanation/aix/mnist/requirements.txt b/docs/samples/explanation/aix/mnist/requirements.txt
index 71ee1712fd..81b5381b8a 100644
--- a/docs/samples/explanation/aix/mnist/requirements.txt
+++ b/docs/samples/explanation/aix/mnist/requirements.txt
@@ -63,7 +63,7 @@ pickleshare==0.7.5
 Pillow==7.1.0
 prometheus-client==0.7.1
 prompt-toolkit==3.0.5
-protobuf==3.11.3
+protobuf==3.15.6
 ptyprocess==0.6.0
 Pygments==2.6.1
 pyparsing==2.4.7