diff --git a/package.json b/package.json
index 40e7c17a..2e5f1b1d 100644
--- a/package.json
+++ b/package.json
@@ -105,7 +105,7 @@
     "npm-run-all": "^4.1.1",
     "selenium-standalone": "^6.13.0",
     "sinon": "^6.0.0",
-    "supertest": "^3.0.0"
+    "supertest": "^4.0.0"
   },
   "ava": {
     "files": [
diff --git a/yarn.lock b/yarn.lock
index aa464756..98b29458 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2404,6 +2404,13 @@ combined-stream@1.0.6, combined-stream@^1.0.5, combined-stream@~1.0.5:
   dependencies:
     delayed-stream "~1.0.0"
 
+combined-stream@^1.0.6:
+  version "1.0.7"
+  resolved "https://registry.yarnpkg.com/combined-stream/-/combined-stream-1.0.7.tgz#2d1d24317afb8abe95d6d2c0b07b57813539d828"
+  integrity sha512-brWl9y6vOB1xYPZcpZde3N9zDByXTosAeMDo4p1wzo6UMOX4vumB+TP1RZ76sfE6Md68Q0NJSrE/gbezd4Ul+w==
+  dependencies:
+    delayed-stream "~1.0.0"
+
 commander@2.15.1:
   version "2.15.1"
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.15.1.tgz#df46e867d0fc2aec66a34662b406a9ccafff5b0f"
@@ -2555,9 +2562,10 @@ cookie@0.3.1:
   version "0.3.1"
   resolved "https://registry.yarnpkg.com/cookie/-/cookie-0.3.1.tgz#e7e0a1f9ef43b4c8ba925c5c5a96e806d16873bb"
 
-cookiejar@^2.1.0:
+cookiejar@^2.1.2:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/cookiejar/-/cookiejar-2.1.2.tgz#dd8a235530752f988f9a0844f3fc589e3111125c"
+  integrity sha512-Mw+adcfzPxcPeI+0WlvRrr/3lGVO0bD75SxX6811cxSh1Wbxx7xZBGK1eVtDf6si8rg2lhnUjsVLMFMfbRIuwA==
 
 copy-concurrently@^1.0.0:
   version "1.0.5"
@@ -2917,6 +2925,13 @@ debug@3.1.0, debug@^3.0.0, debug@^3.0.1, debug@^3.1.0, debug@~3.1.0:
   dependencies:
     ms "2.0.0"
 
+debug@^4.1.0:
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/debug/-/debug-4.1.1.tgz#3b72260255109c6b589cee050f1d516139664791"
+  integrity sha512-pYAIzeRo8J6KPEaJ0VWOh5Pzkbw/RetuzehGM7QRRX5he4fPHx2rdKMB256ehJCkX+XRQm16eZLqLNS8RSZXZw==
+  dependencies:
+    ms "^2.1.1"
+
 decache@^3.0.5:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/decache/-/decache-3.1.0.tgz#4f5036fbd6581fcc97237ac3954a244b9536c2da"
@@ -3818,7 +3833,7 @@ extend-shallow@^3.0.0, extend-shallow@^3.0.2:
     assign-symbols "^1.0.0"
     is-extendable "^1.0.1"
 
-extend@3, extend@^3.0.0, extend@~3.0.0, extend@~3.0.1:
+extend@3, extend@~3.0.0, extend@~3.0.1:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/extend/-/extend-3.0.2.tgz#f8b1136b4071fbd8eb140aff858b1019ec2915fa"
 
@@ -4126,12 +4141,13 @@ forever-agent@~0.6.1:
   version "0.6.1"
   resolved "https://registry.yarnpkg.com/forever-agent/-/forever-agent-0.6.1.tgz#fbc71f0c41adeb37f96c577ad1ed42d8fdacca91"
 
-form-data@^2.3.1, form-data@~2.3.1:
-  version "2.3.2"
-  resolved "https://registry.yarnpkg.com/form-data/-/form-data-2.3.2.tgz#4970498be604c20c005d4f5c23aecd21d6b49099"
+form-data@^2.3.3:
+  version "2.3.3"
+  resolved "https://registry.yarnpkg.com/form-data/-/form-data-2.3.3.tgz#dcce52c05f644f298c6a7ab936bd724ceffbf3a6"
+  integrity sha512-1lLKB2Mu3aGP1Q/2eCOx0fNbRMe7XdwktwOruhfqqd0rIJWwN4Dh+E3hrPSlDCXnSR7UtZ1N38rVXm+6+MEhJQ==
   dependencies:
     asynckit "^0.4.0"
-    combined-stream "1.0.6"
+    combined-stream "^1.0.6"
     mime-types "^2.1.12"
 
 form-data@~2.1.1:
@@ -4142,9 +4158,18 @@ form-data@~2.1.1:
     combined-stream "^1.0.5"
     mime-types "^2.1.12"
 
-formidable@^1.1.1:
+form-data@~2.3.1:
+  version "2.3.2"
+  resolved "https://registry.yarnpkg.com/form-data/-/form-data-2.3.2.tgz#4970498be604c20c005d4f5c23aecd21d6b49099"
+  dependencies:
+    asynckit "^0.4.0"
+    combined-stream "1.0.6"
+    mime-types "^2.1.12"
+
+formidable@^1.2.0:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/formidable/-/formidable-1.2.1.tgz#70fb7ca0290ee6ff961090415f4b3df3d2082659"
+  integrity sha512-Fs9VRguL0gqGHkXS5GQiMCr1VhZBxz0JnJs4JmMp/2jL18Fmbzvv7vOFRU+U8TBkHEE/CX1qDXzJplVULgsLeg==
 
 forwarded@~0.1.2:
   version "0.1.2"
@@ -6102,7 +6127,7 @@ merge-descriptors@1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/merge-descriptors/-/merge-descriptors-1.0.1.tgz#b00aaa556dd8b44568150ec9d1b953f3f90cbb61"
 
-methods@^1.0.0, methods@^1.1.1, methods@~1.1.2:
+methods@^1.0.0, methods@^1.1.1, methods@^1.1.2, methods@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/methods/-/methods-1.1.2.tgz#5529a4d67654134edcc5266656835b0f851afcee"
 
@@ -6163,14 +6188,15 @@ mime@1.4.1:
   version "1.4.1"
   resolved "https://registry.yarnpkg.com/mime/-/mime-1.4.1.tgz#121f9ebc49e3766f311a76e1fa1c8003c4b03aa6"
 
-mime@^1.4.1:
-  version "1.6.0"
-  resolved "https://registry.yarnpkg.com/mime/-/mime-1.6.0.tgz#32cd9e5c64553bd58d19a568af452acff04981b1"
-
 mime@^2.0.3:
   version "2.3.1"
   resolved "https://registry.yarnpkg.com/mime/-/mime-2.3.1.tgz#b1621c54d63b97c47d3cfe7f7215f7d64517c369"
 
+mime@^2.4.0:
+  version "2.4.0"
+  resolved "https://registry.yarnpkg.com/mime/-/mime-2.4.0.tgz#e051fd881358585f3279df333fe694da0bcffdd6"
+  integrity sha512-ikBcWwyqXQSHKtciCcctu9YfPbFYZ4+gbHEmE0Q8jzcTYQg5dHCr3g2wwAZjPoJfQVXZq6KXAjpXOTf5/cjT7w==
+
 mimic-fn@^1.0.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/mimic-fn/-/mimic-fn-1.2.0.tgz#820c86a39334640e99516928bd03fca88057d022"
@@ -7642,10 +7668,15 @@ qs@6.5.1:
   version "6.5.1"
   resolved "https://registry.yarnpkg.com/qs/-/qs-6.5.1.tgz#349cdf6eef89ec45c12d7d5eb3fc0c870343a6d8"
 
-qs@6.5.2, qs@^6.5.1, qs@~6.5.1:
+qs@6.5.2, qs@~6.5.1:
   version "6.5.2"
   resolved "https://registry.yarnpkg.com/qs/-/qs-6.5.2.tgz#cb3ae806e8740444584ef154ce8ee98d403f3e36"
 
+qs@^6.6.0:
+  version "6.6.0"
+  resolved "https://registry.yarnpkg.com/qs/-/qs-6.6.0.tgz#a99c0f69a8d26bf7ef012f871cdabb0aee4424c2"
+  integrity sha512-KIJqT9jQJDQx5h5uAVPimw6yVg2SekOKu959OCtktD3FjzbpvaPr8i4zzg07DOMz+igA4W/aNM7OV8H37pFYfA==
+
 qs@~6.4.0:
   version "6.4.0"
   resolved "https://registry.yarnpkg.com/qs/-/qs-6.4.0.tgz#13e26d28ad6b0ffaa91312cd3bf708ed351e7233"
@@ -7895,7 +7926,7 @@ read-pkg@^3.0.0:
     normalize-package-data "^2.3.2"
     path-type "^3.0.0"
 
-"readable-stream@1 || 2", readable-stream@2, readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.4, readable-stream@^2.0.5, readable-stream@^2.0.6, readable-stream@^2.1.5, readable-stream@^2.2.2, readable-stream@^2.3.0, readable-stream@^2.3.3, readable-stream@^2.3.5, readable-stream@^2.3.6:
+"readable-stream@1 || 2", readable-stream@2, readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.4, readable-stream@^2.0.6, readable-stream@^2.1.5, readable-stream@^2.2.2, readable-stream@^2.3.0, readable-stream@^2.3.3, readable-stream@^2.3.5, readable-stream@^2.3.6:
   version "2.3.6"
   resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.3.6.tgz#b11c27d88b8ff1fbe070643cf94b0c79ae1b0aaf"
   dependencies:
@@ -7925,6 +7956,15 @@ readable-stream@1.1.x:
     isarray "0.0.1"
     string_decoder "~0.10.x"
 
+readable-stream@^3.0.6:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-3.2.0.tgz#de17f229864c120a9f56945756e4f32c4045245d"
+  integrity sha512-RV20kLjdmpZuTF1INEb9IA3L68Nmi+Ri7ppZqo78wj//Pn62fCoJyV9zalccNzDD/OuJpMG4f+pfMl8+L6QdGw==
+  dependencies:
+    inherits "^2.0.3"
+    string_decoder "^1.1.1"
+    util-deprecate "^1.0.1"
+
 readdirp@^2.0.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/readdirp/-/readdirp-2.1.0.tgz#4ed0ad060df3073300c48440373f72d1cc642d78"
@@ -9018,6 +9058,13 @@ string_decoder@^1.0.0, string_decoder@~1.1.1:
   dependencies:
     safe-buffer "~5.1.0"
 
+string_decoder@^1.1.1:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/string_decoder/-/string_decoder-1.2.0.tgz#fe86e738b19544afe70469243b2a1ee9240eae8d"
+  integrity sha512-6YqyX6ZWEYguAxgZzHGL7SsCeGx3V2TtOTqZz1xSTSWnqsbWwbptafNyvf/ACquZUXV3DANr5BDIwNYe1mN42w==
+  dependencies:
+    safe-buffer "~5.1.0"
+
 string_decoder@~0.10.x:
   version "0.10.31"
   resolved "https://registry.yarnpkg.com/string_decoder/-/string_decoder-0.10.31.tgz#62e203bc41766c6c28c9fc84301dab1c5310fa94"
@@ -9085,20 +9132,20 @@ style-loader@^0.21.0:
     loader-utils "^1.1.0"
     schema-utils "^0.4.5"
 
-superagent@3.8.2:
-  version "3.8.2"
-  resolved "https://registry.yarnpkg.com/superagent/-/superagent-3.8.2.tgz#e4a11b9d047f7d3efeb3bbe536d9ec0021d16403"
+superagent@^4.1.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/superagent/-/superagent-4.1.0.tgz#c465c2de41df2b8d05c165cbe403e280790cdfd5"
+  integrity sha512-FT3QLMasz0YyCd4uIi5HNe+3t/onxMyEho7C3PSqmti3Twgy2rXT4fmkTz6wRL6bTF4uzPcfkUCa8u4JWHw8Ag==
   dependencies:
     component-emitter "^1.2.0"
-    cookiejar "^2.1.0"
-    debug "^3.1.0"
-    extend "^3.0.0"
-    form-data "^2.3.1"
-    formidable "^1.1.1"
+    cookiejar "^2.1.2"
+    debug "^4.1.0"
+    form-data "^2.3.3"
+    formidable "^1.2.0"
     methods "^1.1.1"
-    mime "^1.4.1"
-    qs "^6.5.1"
-    readable-stream "^2.0.5"
+    mime "^2.4.0"
+    qs "^6.6.0"
+    readable-stream "^3.0.6"
 
 supertap@^1.0.0:
   version "1.0.0"
@@ -9110,12 +9157,13 @@ supertap@^1.0.0:
     serialize-error "^2.1.0"
     strip-ansi "^4.0.0"
 
-supertest@^3.0.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/supertest/-/supertest-3.1.0.tgz#f9ebaf488e60f2176021ec580bdd23ad269e7bc6"
+supertest@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/supertest/-/supertest-4.0.0.tgz#1fda3a5faf331b20ad5fb836ddf789e80b365db6"
+  integrity sha512-e3UaSMkmVaPQ10MHqb5T9G1mb3L6MVUtLTxkVhKWndHfXyZylwtkjWXD9FzyHqlZ1/EPfeTJ+QDtmax5fb02cw==
   dependencies:
-    methods "~1.1.2"
-    superagent "3.8.2"
+    methods "^1.1.2"
+    superagent "^4.1.0"
 
 supports-color@5.4.0, supports-color@^5.0.0, supports-color@^5.2.0, supports-color@^5.3.0, supports-color@^5.4.0:
   version "5.4.0"
@@ -9606,7 +9654,7 @@ util-arity@^1.0.2:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/util-arity/-/util-arity-1.1.0.tgz#59d01af1fdb3fede0ac4e632b0ab5f6ce97c9330"
 
-util-deprecate@~1.0.1:
+util-deprecate@^1.0.1, util-deprecate@~1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/util-deprecate/-/util-deprecate-1.0.2.tgz#450d4dc9fa70de732762fbd2d4a28981419a0ccf"