diff --git a/.circleci/config.yml b/.circleci/config.yml
index a35ef3b7c..939610467 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -431,12 +431,12 @@ jobs:
       - checkout
       - restore_cache:
           keys:
-            - dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}
+            - dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}-{{ checksum ".circleci/osx_install_dependencies.sh" }}
       - run:
           name: Install build dependencies
           command: ./.circleci/osx_install_dependencies.sh
       - save_cache:
-          key: dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}
+          key: dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}-{{ checksum ".circleci/osx_install_dependencies.sh" }}
           paths:
             - /usr/local/bin
             - /usr/local/sbin
@@ -459,7 +459,7 @@ jobs:
       - checkout
       - restore_cache:
           keys:
-            - dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}
+            - dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}-{{ checksum ".circleci/osx_install_dependencies.sh" }}
       - attach_workspace:
           at: build
       - run: *run_soltest
@@ -475,7 +475,7 @@ jobs:
       - checkout
       - restore_cache:
           keys:
-            - dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}
+            - dependencies-osx-{{ .Branch }}-{{ checksum ".circleci/config.yml" }}-{{ checksum ".circleci/osx_install_dependencies.sh" }}
       - attach_workspace:
           at: build
       - run: *run_cmdline_tests
diff --git a/.circleci/osx_install_dependencies.sh b/.circleci/osx_install_dependencies.sh
index 99c447e0f..22e14af7e 100755
--- a/.circleci/osx_install_dependencies.sh
+++ b/.circleci/osx_install_dependencies.sh
@@ -43,13 +43,13 @@ then
   ./scripts/install_obsolete_jsoncpp_1_7_4.sh
 
   # z3
-  wget https://github.com/Z3Prover/z3/releases/download/Z3-4.8.5/z3-4.8.5-x64-osx-10.14.2.zip
-  unzip z3-4.8.5-x64-osx-10.14.2.zip
-  rm -f z3-4.8.5-x64-osx-10.14.2.zip
-  cp z3-4.8.5-x64-osx-10.14.2/bin/libz3.a /usr/local/lib
-  cp z3-4.8.5-x64-osx-10.14.2/bin/z3 /usr/local/bin
-  cp z3-4.8.5-x64-osx-10.14.2/include/* /usr/local/include
-  rm -rf z3-4.8.5-x64-osx-10.14.2
+  wget https://github.com/Z3Prover/z3/releases/download/z3-4.8.6/z3-4.8.6-x64-osx-10.14.6.zip
+  unzip z3-4.8.6-x64-osx-10.14.6.zip
+  rm -f z3-4.8.6-x64-osx-10.14.6.zip
+  cp z3-4.8.6-x64-osx-10.14.6/bin/libz3.a /usr/local/lib
+  cp z3-4.8.6-x64-osx-10.14.6/bin/z3 /usr/local/bin
+  cp z3-4.8.6-x64-osx-10.14.6/include/* /usr/local/include
+  rm -rf z3-4.8.6-x64-osx-10.14.6
 
   # evmone
   wget https://github.com/ethereum/evmone/releases/download/v0.1.0/evmone-0.1.0-darwin-x86_64.tar.gz