diff --git a/README.md b/README.md
index caadcbf..0e15dea 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,7 @@ See [this](scripts/aws_caper_server/README.md) for details.
 1) Make sure that you have Java (>= 11) and Python>=3.6 installed on your system and `pip` to install Caper.
 
 	```bash
+        $ pip install pip --upgrade
 	$ pip install caper
 	```
 
diff --git a/scripts/gcp_caper_server/create_instance.sh b/scripts/gcp_caper_server/create_instance.sh
index 15aca0a..7cf211e 100755
--- a/scripts/gcp_caper_server/create_instance.sh
+++ b/scripts/gcp_caper_server/create_instance.sh
@@ -295,7 +295,6 @@ sudo psql -d $POSTGRESQL_DB_NAME -c \"create role $POSTGRESQL_DB_USER with super
 
 ### upgrade pip and install caper croo
 sudo python3 -m pip install --upgrade pip
-sudo pip install PyYAML --ignore-installed
 sudo pip install caper croo
 """
 
diff --git a/setup.py b/setup.py
index ce4b41e..fa3f92d 100644
--- a/setup.py
+++ b/setup.py
@@ -69,5 +69,6 @@ def find_meta(meta):
         'scikit-learn>=0.19.2',
         'matplotlib>=1.5',
         'six>=1.13.0',
+        'pyyaml<=5.5',
     ],
 )