diff --git a/README.md b/README.md
index f31f1e2..e2ee9cf 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
 # Vim Vixen
 
+[![Greenkeeper badge](https://badges.greenkeeper.io/ueokande/vim-vixen.svg)](https://greenkeeper.io/)
+
 [![Join the chat room on Gitter for vim-vixen/vim-vixen](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/vim-vixen/vim-vixen)
 [![CircleCI](https://circleci.com/gh/ueokande/vim-vixen.svg?style=svg)](https://circleci.com/gh/ueokande/vim-vixen)
 [![devDependencies Status](https://david-dm.org/ueokande/vim-vixen/dev-status.svg)](https://david-dm.org/ueokande/vim-vixen?type=dev)
diff --git a/package.json b/package.json
index 27413f6..7feed45 100644
--- a/package.json
+++ b/package.json
@@ -38,12 +38,12 @@
     "karma-mocha": "^1.3.0",
     "karma-mocha-reporter": "^2.2.3",
     "karma-sourcemap-loader": "^0.3.7",
-    "karma-webpack": "^2.0.13",
+    "karma-webpack": "^3.0.0",
     "mocha": "^5.0.0",
     "node-sass": "^4.5.3",
     "preact": "^8.2.6",
-    "sass-loader": "^6.0.7",
-    "style-loader": "^0.20.3",
+    "sass-loader": "^7.0.1",
+    "style-loader": "^0.21.0",
     "web-ext": "github:ueokande/web-ext#patched-2.4.0",
     "webpack": "^4.1.1",
     "webpack-cli": "^2.0.11"