diff --git a/.circleci/config.yml b/.circleci/config.yml
index 154118ee..857d4427 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,32 +3,24 @@ workflows:
   version: 2
   tests:
     jobs: &workflow_jobs
-      - node4:
+      - node6:
           filters: &all_commits
             tags:
               only: /.*/
-      - node6:
-          filters: *all_commits
       - node8:
           filters: *all_commits
-      - node9:
-          filters: *all_commits
       - node10:
           filters: *all_commits
       - lint:
           requires:
-            - node4
             - node6
             - node8
-            - node9
             - node10
           filters: *all_commits
       - docs:
           requires:
-            - node4
             - node6
             - node8
-            - node9
             - node10
           filters: *all_commits
       - system_tests:
@@ -62,9 +54,9 @@ workflows:
               only: master
     jobs: *workflow_jobs
 jobs:
-  node4:
+  node6:
     docker:
-      - image: 'node:4'
+      - image: 'node:6'
         user: node
     steps: &unit_tests_steps
       - checkout
@@ -84,7 +76,6 @@ jobs:
           command: |-
             mkdir -p /home/node/.npm-global
             npm install
-            npm link
             chmod +x node_modules/@google-cloud/nodejs-repo-tools/bin/tools
           environment:
             NPM_CONFIG_PREFIX: /home/node/.npm-global
@@ -95,21 +86,11 @@ jobs:
           name: Submit coverage data to codecov.
           command: node_modules/.bin/codecov
           when: always
-  node6:
-    docker:
-      - image: 'node:6'
-        user: node
-    steps: *unit_tests_steps
   node8:
     docker:
       - image: 'node:8'
         user: node
     steps: *unit_tests_steps
-  node9:
-    docker:
-      - image: 'node:9'
-        user: node
-    steps: *unit_tests_steps
   node10:
     docker:
       - image: 'node:10'
@@ -127,7 +108,7 @@ jobs:
           name: Link the module being tested to the samples.
           command: |
             cd samples/
-            npm link @google-cloud/bigquery
+            npm link ../
             npm install
             cd ..
           environment:
diff --git a/package.json b/package.json
index a8b3939a..dff983cb 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
   "license": "Apache-2.0",
   "author": "Google LLC",
   "engines": {
-    "node": ">=4.0.0"
+    "node": ">=6.0.0"
   },
   "repository": "googleapis/nodejs-bigquery",
   "main": "./src/index.js",