diff --git a/themes-default/slim/package.json b/themes-default/slim/package.json
index 8f808bdd61..da6ca7b121 100644
--- a/themes-default/slim/package.json
+++ b/themes-default/slim/package.json
@@ -39,7 +39,6 @@
     "browser-env": "3.2.5",
     "browserify": "16.2.2",
     "codecov": "3.0.4",
-    "concurrently": "3.6.0",
     "cross-env": "5.2.0",
     "eslint": "5.2.0",
     "eslint-config-xo": "0.23.0",
diff --git a/themes-default/slim/yarn.lock b/themes-default/slim/yarn.lock
index ffe09f2bd3..a02cbd3284 100644
--- a/themes-default/slim/yarn.lock
+++ b/themes-default/slim/yarn.lock
@@ -1943,10 +1943,6 @@ combined-stream@1.0.6, combined-stream@~1.0.5:
   dependencies:
     delayed-stream "~1.0.0"
 
-commander@2.6.0:
-  version "2.6.0"
-  resolved "https://registry.yarnpkg.com/commander/-/commander-2.6.0.tgz#9df7e52fb2a0cb0fb89058ee80c3104225f37e1d"
-
 commander@~2.16.0:
   version "2.16.0"
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.16.0.tgz#f16390593996ceb4f3eeb020b31d78528f7f8a50"
@@ -1998,20 +1994,6 @@ concordance@^3.0.0:
     semver "^5.3.0"
     well-known-symbols "^1.0.0"
 
-concurrently@3.6.0:
-  version "3.6.0"
-  resolved "https://registry.yarnpkg.com/concurrently/-/concurrently-3.6.0.tgz#c25e34b156a9d5bd4f256a0d85f6192438ae481f"
-  dependencies:
-    chalk "^2.4.1"
-    commander "2.6.0"
-    date-fns "^1.23.0"
-    lodash "^4.5.1"
-    read-pkg "^3.0.0"
-    rx "2.3.24"
-    spawn-command "^0.0.2-1"
-    supports-color "^3.2.3"
-    tree-kill "^1.1.0"
-
 config-chain@^1.1.11:
   version "1.1.11"
   resolved "https://registry.yarnpkg.com/config-chain/-/config-chain-1.1.11.tgz#aba09747dfbe4c3e70e766a6e41586e1859fc6f2"
@@ -2293,10 +2275,6 @@ data-uri-to-buffer@1:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/data-uri-to-buffer/-/data-uri-to-buffer-1.2.0.tgz#77163ea9c20d8641b4707e8f18abdf9a78f34835"
 
-date-fns@^1.23.0:
-  version "1.29.0"
-  resolved "https://registry.yarnpkg.com/date-fns/-/date-fns-1.29.0.tgz#12e609cdcb935127311d04d33334e2960a2a54e6"
-
 date-now@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/date-now/-/date-now-0.1.4.tgz#eaf439fd4d4848ad74e5cc7dbef200672b9e345b"
@@ -5712,7 +5690,7 @@ lodash.zip@^4.2.0:
   version "4.2.0"
   resolved "https://registry.yarnpkg.com/lodash.zip/-/lodash.zip-4.2.0.tgz#ec6662e4896408ed4ab6c542a3990b72cc080020"
 
-lodash@^4.11.1, lodash@^4.13.1, lodash@^4.17.10, lodash@^4.17.4, lodash@^4.17.5, lodash@^4.3.0, lodash@^4.5.1:
+lodash@^4.11.1, lodash@^4.13.1, lodash@^4.17.10, lodash@^4.17.4, lodash@^4.17.5, lodash@^4.3.0:
   version "4.17.10"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.10.tgz#1b7793cf7259ea38fb3661d4d38b3260af8ae4e7"
 
@@ -7635,10 +7613,6 @@ rx-lite@*, rx-lite@^4.0.8:
   version "4.0.8"
   resolved "https://registry.yarnpkg.com/rx-lite/-/rx-lite-4.0.8.tgz#0b1e11af8bc44836f04a6407e92da42467b79444"
 
-rx@2.3.24:
-  version "2.3.24"
-  resolved "https://registry.yarnpkg.com/rx/-/rx-2.3.24.tgz#14f950a4217d7e35daa71bbcbe58eff68ea4b2b7"
-
 rxjs@^5.5.2:
   version "5.5.11"
   resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-5.5.11.tgz#f733027ca43e3bec6b994473be4ab98ad43ced87"
@@ -8087,10 +8061,6 @@ sparkles@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/sparkles/-/sparkles-1.0.1.tgz#008db65edce6c50eec0c5e228e1945061dd0437c"
 
-spawn-command@^0.0.2-1:
-  version "0.0.2-1"
-  resolved "https://registry.yarnpkg.com/spawn-command/-/spawn-command-0.0.2-1.tgz#62f5e9466981c1b796dc5929937e11c9c6921bd0"
-
 spawn-wrap@^1.4.2:
   version "1.4.2"
   resolved "https://registry.yarnpkg.com/spawn-wrap/-/spawn-wrap-1.4.2.tgz#cff58e73a8224617b6561abdc32586ea0c82248c"
@@ -8718,10 +8688,6 @@ tr46@^1.0.1:
   dependencies:
     punycode "^2.1.0"
 
-tree-kill@^1.1.0:
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/tree-kill/-/tree-kill-1.2.0.tgz#5846786237b4239014f05db156b643212d4c6f36"
-
 trim-newlines@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/trim-newlines/-/trim-newlines-1.0.0.tgz#5887966bb582a4503a41eb524f7d35011815a613"