diff --git a/requirements-dev.txt b/requirements-dev.txt
index 99f6cc3678..ac8b3730d8 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -40,7 +40,7 @@ pandas
 requests
 einops
 transformers
-mlflow!=1.26.1  # https://github.com/Project-MONAI/MONAI/issues/4375
+mlflow
 matplotlib!=3.5.0
 tensorboardX
 types-PyYAML
diff --git a/runtests.sh b/runtests.sh
index ec9493f6b2..f7403ff05b 100755
--- a/runtests.sh
+++ b/runtests.sh
@@ -15,7 +15,11 @@
 set -e
 
 # FIXME: https://github.com/Project-MONAI/MONAI/issues/4354
-export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python
+protobuf_major_version=$(pip list | grep '^protobuf ' | tr -s ' ' | cut -d' ' -f2 | cut -d'.' -f1)
+if [ "$protobuf_major_version" -ge "4" ]
+then
+    export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python
+fi
 
 # output formatting
 separator=""