diff --git a/lib/KarmaWebpackController.js b/lib/KarmaWebpackController.js
index 901e63a..ad2e0f7 100644
--- a/lib/KarmaWebpackController.js
+++ b/lib/KarmaWebpackController.js
@@ -5,7 +5,7 @@ const fs = require('fs');
 const os = require('os');
 
 const webpack = require('webpack');
-const merge = require('merge');
+const merge = require('webpack-merge');
 
 class KarmaSyncPlugin {
   constructor(options) {
@@ -118,8 +118,7 @@ class KarmaWebpackController {
   }
 
   updateWebpackOptions(newOptions) {
-    this.__webpackOptions = merge.recursive(
-      true,
+    this.__webpackOptions = merge(
       this.__webpackOptions,
       newOptions
     );
diff --git a/package-lock.json b/package-lock.json
index 974d0db..f0c3d72 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "karma-webpack",
-  "version": "4.0.0-rc.5",
+  "version": "5.0.0-rc.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -923,6 +923,7 @@
       "resolved": "https://registry.npmjs.org/align-text/-/align-text-0.1.4.tgz",
       "integrity": "sha1-DNkKVhCT810KmSVsIrcGlDP60Rc=",
       "dev": true,
+      "optional": true,
       "requires": {
         "kind-of": "^3.0.2",
         "longest": "^1.0.1",
@@ -944,11 +945,6 @@
         "string-width": "^2.0.0"
       }
     },
-    "ansi-colors": {
-      "version": "3.0.5",
-      "resolved": "https://registry.npmjs.org/ansi-colors/-/ansi-colors-3.0.5.tgz",
-      "integrity": "sha512-VVjWpkfaphxUBFarydrQ3n26zX5nIK7hcbT3/ielrvwDDyBBjuh2vuSw1P9zkPq0cfqvdw7lkYHnu+OLSfIBsg=="
-    },
     "ansi-escapes": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-3.1.0.tgz",
@@ -1034,7 +1030,8 @@
     "array-find-index": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/array-find-index/-/array-find-index-1.0.2.tgz",
-      "integrity": "sha1-3wEKoSh+Fku9pvlyOwqWoexBh6E="
+      "integrity": "sha1-3wEKoSh+Fku9pvlyOwqWoexBh6E=",
+      "dev": true
     },
     "array-ify": {
       "version": "1.0.0",
@@ -1155,6 +1152,7 @@
       "version": "2.6.0",
       "resolved": "https://registry.npmjs.org/async/-/async-2.6.0.tgz",
       "integrity": "sha512-xAfGg1/NTLBBKlHFmnd7PlmUW9KhVQIUuSrYem9xzFUZy13ScvtyGGejaae9iAVRiRq9+Cx7DPFaAAhCpyxyPw==",
+      "dev": true,
       "requires": {
         "lodash": "^4.14.0"
       }
@@ -1334,13 +1332,15 @@
           "version": "1.0.0",
           "resolved": "https://registry.npmjs.org/is-extglob/-/is-extglob-1.0.0.tgz",
           "integrity": "sha1-rEaBd8SUNAWgkvyPKXYMb/xiBsA=",
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "is-glob": {
           "version": "2.0.1",
           "resolved": "https://registry.npmjs.org/is-glob/-/is-glob-2.0.1.tgz",
           "integrity": "sha1-0Jb5JqPe1WAPP9/ZEZjLCIjC2GM=",
           "dev": true,
+          "optional": true,
           "requires": {
             "is-extglob": "^1.0.0"
           }
@@ -2180,7 +2180,8 @@
     "big.js": {
       "version": "3.2.0",
       "resolved": "https://registry.npmjs.org/big.js/-/big.js-3.2.0.tgz",
-      "integrity": "sha512-+hN/Zh2D08Mx65pZ/4g5bsmNiZUuChDiQfTUQ7qJr4/kuopCr88xZsAXv6mBoZEsUI4OuGHlX59qE94K2mMW8Q=="
+      "integrity": "sha512-+hN/Zh2D08Mx65pZ/4g5bsmNiZUuChDiQfTUQ7qJr4/kuopCr88xZsAXv6mBoZEsUI4OuGHlX59qE94K2mMW8Q==",
+      "dev": true
     },
     "binary-extensions": {
       "version": "1.11.0",
@@ -4207,7 +4208,8 @@
     "core-util-is": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/core-util-is/-/core-util-is-1.0.2.tgz",
-      "integrity": "sha1-tf1UIgqivFq1eqtxQMlAdUUDwac="
+      "integrity": "sha1-tf1UIgqivFq1eqtxQMlAdUUDwac=",
+      "dev": true
     },
     "cosmiconfig": {
       "version": "4.0.0",
@@ -4359,6 +4361,7 @@
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/currently-unhandled/-/currently-unhandled-0.4.1.tgz",
       "integrity": "sha1-mI3zP+qxke95mmE2nddsF635V+o=",
+      "dev": true,
       "requires": {
         "array-find-index": "^1.0.1"
       }
@@ -4779,7 +4782,8 @@
     "emojis-list": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/emojis-list/-/emojis-list-2.1.0.tgz",
-      "integrity": "sha1-TapNnbAPmBmIDHn6RXrlsJof04k="
+      "integrity": "sha1-TapNnbAPmBmIDHn6RXrlsJof04k=",
+      "dev": true
     },
     "encodeurl": {
       "version": "1.0.2",
@@ -4885,6 +4889,7 @@
       "version": "0.1.7",
       "resolved": "https://registry.npmjs.org/errno/-/errno-0.1.7.tgz",
       "integrity": "sha512-MfrRBDWzIWifgq6tJj60gkAwtLNb6sQPlcFrSOflcP1aFmmruKQ2wRnze/8V6kgyz7H3FF8Npzv78mZ7XLLflg==",
+      "dev": true,
       "requires": {
         "prr": "~1.0.1"
       }
@@ -6028,7 +6033,8 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -6443,7 +6449,8 @@
         "safe-buffer": {
           "version": "5.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -6499,6 +6506,7 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -6542,12 +6550,14 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "yallist": {
           "version": "3.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         }
       }
     },
@@ -8103,7 +8113,8 @@
     "isarray": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/isarray/-/isarray-1.0.0.tgz",
-      "integrity": "sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE="
+      "integrity": "sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE=",
+      "dev": true
     },
     "isbinaryfile": {
       "version": "3.0.3",
@@ -10242,7 +10253,8 @@
     "json5": {
       "version": "0.5.1",
       "resolved": "https://registry.npmjs.org/json5/-/json5-0.5.1.tgz",
-      "integrity": "sha1-Hq3nrMASA0rYTiOWdn6tn6VJWCE="
+      "integrity": "sha1-Hq3nrMASA0rYTiOWdn6tn6VJWCE=",
+      "dev": true
     },
     "jsonfile": {
       "version": "4.0.0",
@@ -10690,6 +10702,7 @@
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/loader-utils/-/loader-utils-1.1.0.tgz",
       "integrity": "sha1-yYrvSIvM7aL/teLeZG1qdUQp9c0=",
+      "dev": true,
       "requires": {
         "big.js": "^3.1.3",
         "emojis-list": "^2.0.0",
@@ -10939,7 +10952,8 @@
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/longest/-/longest-1.0.1.tgz",
       "integrity": "sha1-MKCy2jj3N3DoKUoNIuZiXtd9AJc=",
-      "dev": true
+      "dev": true,
+      "optional": true
     },
     "loose-envify": {
       "version": "1.3.1",
@@ -10954,6 +10968,7 @@
       "version": "1.6.0",
       "resolved": "https://registry.npmjs.org/loud-rejection/-/loud-rejection-1.6.0.tgz",
       "integrity": "sha1-W0b4AUft7leIcPCG0Eghz5mOVR8=",
+      "dev": true,
       "requires": {
         "currently-unhandled": "^0.4.1",
         "signal-exit": "^3.0.0"
@@ -11055,6 +11070,7 @@
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/memory-fs/-/memory-fs-0.4.1.tgz",
       "integrity": "sha1-OpoguEYlI+RHz7x+i7gO1me/xVI=",
+      "dev": true,
       "requires": {
         "errno": "^0.1.3",
         "readable-stream": "^2.0.1"
@@ -11087,9 +11103,9 @@
       }
     },
     "merge": {
-      "version": "1.2.0",
-      "resolved": "https://registry.npmjs.org/merge/-/merge-1.2.0.tgz",
-      "integrity": "sha1-dTHjnUlJwoGma4xabgJl6LBYlNo=",
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/merge/-/merge-1.2.1.tgz",
+      "integrity": "sha512-VjFo4P5Whtj4vsLzsYBu5ayHhoHJ0UqNm7ibvShmbmoz7tGi0vXaoJbGdB+GmDMLUdg8DpQXEIeVDAe8MaABvQ==",
       "dev": true
     },
     "merge-stream": {
@@ -11143,7 +11159,8 @@
     "mime": {
       "version": "2.3.1",
       "resolved": "https://registry.npmjs.org/mime/-/mime-2.3.1.tgz",
-      "integrity": "sha512-OEUllcVoydBHGN1z84yfQDimn58pZNNNXgZlHXSboxMlFvgI6MXSWpWKpFRra7H1HxpVhHTkrghfRW49k6yjeg=="
+      "integrity": "sha512-OEUllcVoydBHGN1z84yfQDimn58pZNNNXgZlHXSboxMlFvgI6MXSWpWKpFRra7H1HxpVhHTkrghfRW49k6yjeg==",
+      "dev": true
     },
     "mime-db": {
       "version": "1.36.0",
@@ -12596,7 +12613,8 @@
     "process-nextick-args": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/process-nextick-args/-/process-nextick-args-2.0.0.tgz",
-      "integrity": "sha512-MtEC1TqN0EU5nephaJ4rAtThHtC86dNN9qCuEhtshvpVBkAW5ZO7BASN9REnF9eoXGcRub+pFuKEpOHE+HbEMw=="
+      "integrity": "sha512-MtEC1TqN0EU5nephaJ4rAtThHtC86dNN9qCuEhtshvpVBkAW5ZO7BASN9REnF9eoXGcRub+pFuKEpOHE+HbEMw==",
+      "dev": true
     },
     "progress": {
       "version": "2.0.0",
@@ -12640,7 +12658,8 @@
     "prr": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/prr/-/prr-1.0.1.tgz",
-      "integrity": "sha1-0/wRS6BplaRexok/SEzrHXj19HY="
+      "integrity": "sha1-0/wRS6BplaRexok/SEzrHXj19HY=",
+      "dev": true
     },
     "pseudomap": {
       "version": "1.0.2",
@@ -12788,7 +12807,8 @@
     "range-parser": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/range-parser/-/range-parser-1.2.0.tgz",
-      "integrity": "sha1-9JvmtIeJTdxA3MlKMi9hEJLgDV4="
+      "integrity": "sha1-9JvmtIeJTdxA3MlKMi9hEJLgDV4=",
+      "dev": true
     },
     "raw-body": {
       "version": "2.3.3",
@@ -12864,6 +12884,7 @@
       "version": "2.3.4",
       "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.4.tgz",
       "integrity": "sha512-vuYxeWYM+fde14+rajzqgeohAI7YoJcHE7kXDAc4Nk0EbuKnJfqtY9YtRkLo/tqkuF7MsBQRhPnPeyjYITp3ZQ==",
+      "dev": true,
       "requires": {
         "core-util-is": "~1.0.0",
         "inherits": "~2.0.3",
@@ -13302,7 +13323,8 @@
     "safe-buffer": {
       "version": "5.1.1",
       "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.1.tgz",
-      "integrity": "sha512-kKvNJn6Mm93gAczWVJg7wH+wGYWNrDHdWvpUmHyEsgCtIwwo3bqPtV4tR5tuPaUhTOo/kvhVwd8XwwOllGYkbg=="
+      "integrity": "sha512-kKvNJn6Mm93gAczWVJg7wH+wGYWNrDHdWvpUmHyEsgCtIwwo3bqPtV4tR5tuPaUhTOo/kvhVwd8XwwOllGYkbg==",
+      "dev": true
     },
     "safe-regex": {
       "version": "1.1.0",
@@ -13480,7 +13502,8 @@
     "signal-exit": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/signal-exit/-/signal-exit-3.0.2.tgz",
-      "integrity": "sha1-tf3AjxKH6hF4Yo5BXiUTK3NkbG0="
+      "integrity": "sha1-tf3AjxKH6hF4Yo5BXiUTK3NkbG0=",
+      "dev": true
     },
     "sisteransi": {
       "version": "0.1.1",
@@ -13752,7 +13775,8 @@
     "source-map": {
       "version": "0.5.7",
       "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
-      "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w="
+      "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
+      "dev": true
     },
     "source-map-resolve": {
       "version": "0.5.1",
@@ -14289,6 +14313,7 @@
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.0.3.tgz",
       "integrity": "sha512-4AH6Z5fzNNBcH+6XDMfA/BTt87skxqJlO0lAh3Dker5zThcAxG6mKz+iGu308UKoPPQ8Dcqx/4JhujzltRa+hQ==",
+      "dev": true,
       "requires": {
         "safe-buffer": "~5.1.0"
       }
@@ -15049,11 +15074,6 @@
         }
       }
     },
-    "url-join": {
-      "version": "4.0.0",
-      "resolved": "https://registry.npmjs.org/url-join/-/url-join-4.0.0.tgz",
-      "integrity": "sha1-TTNA6AfTdzvamZH4MFrNzCpmXSo="
-    },
     "url-parse-lax": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/url-parse-lax/-/url-parse-lax-1.0.0.tgz",
@@ -15131,7 +15151,8 @@
     "util-deprecate": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/util-deprecate/-/util-deprecate-1.0.2.tgz",
-      "integrity": "sha1-RQ1Nyfpw3nMnYvvS1KKJgUGaDM8="
+      "integrity": "sha1-RQ1Nyfpw3nMnYvvS1KKJgUGaDM8=",
+      "dev": true
     },
     "util.promisify": {
       "version": "1.0.0",
@@ -15149,11 +15170,6 @@
       "integrity": "sha1-n5VxD1CiZ5R7LMwSR0HBAoQn5xM=",
       "dev": true
     },
-    "uuid": {
-      "version": "3.3.2",
-      "resolved": "https://registry.npmjs.org/uuid/-/uuid-3.3.2.tgz",
-      "integrity": "sha512-yXJmeNaw3DnnKAOKJE51sL/ZaYfWJRl1pK9dr19YFCu0ObS231AB1/LbqTKRAQ5kw8A90rA6fr4riOUpTZvQZA=="
-    },
     "v8flags": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/v8flags/-/v8flags-2.1.1.tgz",
@@ -15293,34 +15309,10 @@
         }
       }
     },
-    "webpack-dev-middleware": {
-      "version": "3.2.0",
-      "resolved": "https://registry.npmjs.org/webpack-dev-middleware/-/webpack-dev-middleware-3.2.0.tgz",
-      "integrity": "sha512-YJLMF/96TpKXaEQwaLEo+Z4NDK8aV133ROF6xp9pe3gQoS7sxfpXh4Rv9eC+8vCvWfmDjRQaMSlRPbO+9G6jgA==",
-      "requires": {
-        "loud-rejection": "^1.6.0",
-        "memory-fs": "~0.4.1",
-        "mime": "^2.3.1",
-        "path-is-absolute": "^1.0.0",
-        "range-parser": "^1.0.3",
-        "url-join": "^4.0.0",
-        "webpack-log": "^2.0.0"
-      }
-    },
-    "webpack-log": {
-      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/webpack-log/-/webpack-log-2.0.0.tgz",
-      "integrity": "sha512-cX8G2vR/85UYG59FgkoMamwHUIkSSlV3bBMRsbxVXVUk2j6NleCKjQ/WE9eYg9WY4w25O9w8wKP4rzNZFmUcUg==",
-      "requires": {
-        "ansi-colors": "^3.0.0",
-        "uuid": "^3.3.2"
-      }
-    },
     "webpack-merge": {
-      "version": "4.1.4",
-      "resolved": "https://registry.npmjs.org/webpack-merge/-/webpack-merge-4.1.4.tgz",
-      "integrity": "sha512-TmSe1HZKeOPey3oy1Ov2iS3guIZjWvMT2BBJDzzT5jScHTjVC3mpjJofgueEzaEd6ibhxRDD6MIblDr8tzh8iQ==",
-      "dev": true,
+      "version": "4.1.5",
+      "resolved": "https://registry.npmjs.org/webpack-merge/-/webpack-merge-4.1.5.tgz",
+      "integrity": "sha512-sVcM+MMJv6DO0C0GLLltx8mUlGMKXE0zBsuMqZ9jz2X9gsekALw6Rs0cAfTWc97VuWS6NpVUa78959zANnMMLQ==",
       "requires": {
         "lodash": "^4.17.5"
       }
diff --git a/package.json b/package.json
index b367221..fe74cbf 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
   },
   "dependencies": {
     "glob": "^7.1.3",
-    "merge": "^1.2.1"
+    "webpack-merge": "^4.1.5"
   },
   "devDependencies": {
     "@commitlint/cli": "^7.1.1",