diff --git a/.circleci/config.yml b/.circleci/config.yml
index d8ec473b3..75790ebd7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -385,7 +385,7 @@ commands:
       - run: sudo chown -R circleci:circleci /usr/local/bin
       - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
       - save_cache:
-          key: pip-v3-{{ .Branch }}-{{ checksum "Pipfile.lock" }}
+          key: pip-v4-{{ .Branch }}-{{ checksum "Pipfile.lock" }}
           paths:
             - "~/.local/bin"
             - "~/.local/lib/python3.7/site-packages"
@@ -400,7 +400,7 @@ commands:
       - run: sudo chown -R circleci:circleci /usr/local/bin
       - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
       - restore_cache:  # ensure this step occurs *before* installing dependencies
-          key: pip-v3-{{ .Branch }}-{{ checksum "Pipfile.lock" }}
+          key: pip-v4-{{ .Branch }}-{{ checksum "Pipfile.lock" }}
       - restore_cache:
           key: solc-v2-{{ checksum "nucypher/blockchain/eth/sol/__conf__.py" }}