diff --git a/.circleci/config.yml b/.circleci/config.yml
index d2da5c25..64cc7966 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -20,6 +20,10 @@ commands:
             virtualenv --python=python2.7 --always-copy venv
             . venv/bin/activate
             pip install 'wheel>=0.29.0'
+            # Install pinned verison of proobuf first,
+            # as opentracing in the core requirements
+            # would pull in a newer one
+            pip install 'protobuf<4.0.0'
             pip install -r requirements.txt
             pip install -r <<parameters.requirements>>
 
@@ -257,7 +261,6 @@ jobs:
     working_directory: ~/repo
     steps:
       - checkout
-      - install-couchbase-deps
       - pip-install-deps-27:
           requirements: "tests/requirements-cassandra.txt"
       - run:
diff --git a/tests/requirements-27.txt b/tests/requirements-27.txt
index 327eab49..1b8cb0b3 100644
--- a/tests/requirements-27.txt
+++ b/tests/requirements-27.txt
@@ -19,6 +19,14 @@ PyMySQL[rsa]>=0.9.1
 pyOpenSSL>=16.1.0;python_version<="2.7"
 psycopg2>=2.7.1
 pika>=1.0.0
+
+# protobuf is pulled in and also `basictracer`, a core instana dependency
+# and also by google-cloud-storage
+# but also directly needed by tests/apps/grpc_server/stan_pb2.py
+# when protobuf is above 4.0.0 the following error happens:
+# ERROR: Package 'protobuf' requires a different Python: 2.7.16 not in '>=3.7'
+protobuf<4.0.0
+
 pymongo>=3.7.0
 pyramid>=1.2
 pytest>=4.6
diff --git a/tests/requirements-310.txt b/tests/requirements-310.txt
index b6366e63..041c533e 100644
--- a/tests/requirements-310.txt
+++ b/tests/requirements-310.txt
@@ -29,6 +29,15 @@ nose>=1.3.7
 PyMySQL[rsa]>=1.0.2
 psycopg2-binary>=2.8.6
 pika>=1.2.0
+
+# protobuf is pulled in and also `basictracer`, a core instana dependency
+# and also by google-cloud-storage
+# but also directly needed by tests/apps/grpc_server/stan_pb2.py
+# On 4.0.0 we currently get:
+# AttributeError: module 'google._upb._message' has no attribute 'Message'
+# TODO: Remove this when support for 4.0.0 is done
+protobuf<4.0.0
+
 pymongo>=3.11.4
 pyramid>=2.0
 pytest>=6.2.4
diff --git a/tests/requirements.txt b/tests/requirements.txt
index 76f470eb..45f00fd5 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -17,6 +17,15 @@ nose>=1.3.7
 PyMySQL[rsa]>=1.0.2
 psycopg2-binary>=2.8.6
 pika>=1.2.0
+
+# protobuf is pulled in and also `basictracer`, a core instana dependency
+# and also by google-cloud-storage
+# but also directly needed by tests/apps/grpc_server/stan_pb2.py
+# On 4.0.0 we currently get:
+# AttributeError: module 'google._upb._message' has no attribute 'Message'
+# TODO: Remove this when support for 4.0.0 is done
+protobuf<4.0.0
+
 pymongo>=3.11.4
 pyramid>=2.0
 pytest>=6.2.4