diff --git a/demo/audio/server/package.json b/demo/audio/server/package.json
index 5a7f213..2c272ce 100644
--- a/demo/audio/server/package.json
+++ b/demo/audio/server/package.json
@@ -16,7 +16,7 @@
     "@tensorflow/tfjs": "~0.12",
     "@tensorflow/tfjs-node": "^0.1.9",
     "cross-env": "^5.2.0",
-    "express": "^4.16.3",
+    "express": "^4.17.3",
     "express-basic-auth": "^1.1.5",
     "express-fileupload": "^0.4.0",
     "federated-learning-server": "file:../../../src/server",
diff --git a/demo/audio/server/yarn.lock b/demo/audio/server/yarn.lock
index 9d3b3b9..c441bc3 100644
--- a/demo/audio/server/yarn.lock
+++ b/demo/audio/server/yarn.lock
@@ -101,12 +101,13 @@
   dependencies:
     "@types/node" "*"
 
-accepts@~1.3.4, accepts@~1.3.5:
-  version "1.3.5"
-  resolved "https://registry.yarnpkg.com/accepts/-/accepts-1.3.5.tgz#eb777df6011723a3b14e8a72c0805c8e86746bd2"
+accepts@~1.3.4, accepts@~1.3.8:
+  version "1.3.8"
+  resolved "https://registry.yarnpkg.com/accepts/-/accepts-1.3.8.tgz#0bf0be125b67014adcb0b0921e62db7bffe16b2e"
+  integrity sha512-PYAthTa2m2VKxuvSD3DPC/Gy+U+sOA1LAuT8mkmRuvw+NACSaeXEQ+NHcVF7rONl6qcaxV3Uuemwawk+7+SJLw==
   dependencies:
-    mime-types "~2.1.18"
-    negotiator "0.6.1"
+    mime-types "~2.1.34"
+    negotiator "0.6.3"
 
 after@0.8.2:
   version "0.8.2"
@@ -184,20 +185,21 @@ blob@0.0.4:
   version "0.0.4"
   resolved "https://registry.yarnpkg.com/blob/-/blob-0.0.4.tgz#bcf13052ca54463f30f9fc7e95b9a47630a94921"
 
-body-parser@1.18.2:
-  version "1.18.2"
-  resolved "https://registry.yarnpkg.com/body-parser/-/body-parser-1.18.2.tgz#87678a19d84b47d859b83199bd59bce222b10454"
+body-parser@1.19.2:
+  version "1.19.2"
+  resolved "https://registry.yarnpkg.com/body-parser/-/body-parser-1.19.2.tgz#4714ccd9c157d44797b8b5607d72c0b89952f26e"
+  integrity sha512-SAAwOxgoCKMGs9uUAUFHygfLAyaniaoun6I8mFY9pRAJL9+Kec34aU+oIjDhTycub1jozEfEwx1W1IuOYxVSFw==
   dependencies:
-    bytes "3.0.0"
+    bytes "3.1.2"
     content-type "~1.0.4"
     debug "2.6.9"
-    depd "~1.1.1"
-    http-errors "~1.6.2"
-    iconv-lite "0.4.19"
+    depd "~1.1.2"
+    http-errors "1.8.1"
+    iconv-lite "0.4.24"
     on-finished "~2.3.0"
-    qs "6.5.1"
-    raw-body "2.3.2"
-    type-is "~1.6.15"
+    qs "6.9.7"
+    raw-body "2.4.3"
+    type-is "~1.6.18"
 
 brace-expansion@^1.1.7:
   version "1.1.11"
@@ -214,9 +216,10 @@ busboy@^0.2.14:
     dicer "0.2.5"
     readable-stream "1.1.x"
 
-bytes@3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/bytes/-/bytes-3.0.0.tgz#d32815404d689699f85a4ea4fa8755dd13a96048"
+bytes@3.1.2:
+  version "3.1.2"
+  resolved "https://registry.yarnpkg.com/bytes/-/bytes-3.1.2.tgz#8b0beeb98605adf1b128fa4386403c009e0221a5"
+  integrity sha512-/Nf7TyzTx6S3yRJObOAV7956r8cr2+Oj8AC5dt8wSP3BQAoeX58NoHyCU8P8zGkNXStjTSi6fzO6F0pBdcYbEg==
 
 callsite@1.0.0:
   version "1.0.0"
@@ -262,9 +265,12 @@ concat-map@0.0.1:
   resolved "https://registry.yarnpkg.com/concat-map/-/concat-map-0.0.1.tgz#d8a96bd77fd68df7793a73036a3ba0d5405d477b"
   integrity sha1-2Klr13/Wjfd5OnMDajug1UBdR3s=
 
-content-disposition@0.5.2:
-  version "0.5.2"
-  resolved "https://registry.yarnpkg.com/content-disposition/-/content-disposition-0.5.2.tgz#0cf68bb9ddf5f2be7961c3a85178cb85dba78cb4"
+content-disposition@0.5.4:
+  version "0.5.4"
+  resolved "https://registry.yarnpkg.com/content-disposition/-/content-disposition-0.5.4.tgz#8b82b4efac82512a02bb0b1dcec9d2c5e8eb5bfe"
+  integrity sha512-FveZTNuGw04cxlAiWbzi6zTAL/lhehaWbTtgluJh4/E95DqMwTmha3KZN1aAWA8cFIhHzMZUvLevkw5Rqk+tSQ==
+  dependencies:
+    safe-buffer "5.2.1"
 
 content-type@~1.0.4:
   version "1.0.4"
@@ -278,6 +284,11 @@ cookie@0.3.1:
   version "0.3.1"
   resolved "https://registry.yarnpkg.com/cookie/-/cookie-0.3.1.tgz#e7e0a1f9ef43b4c8ba925c5c5a96e806d16873bb"
 
+cookie@0.4.2:
+  version "0.4.2"
+  resolved "https://registry.yarnpkg.com/cookie/-/cookie-0.4.2.tgz#0e41f24de5ecf317947c82fc789e06a884824432"
+  integrity sha512-aSWTXFzaKWkvHO1Ny/s+ePFpvKsPnjc551iI41v3ny/ow6tBG5Vd+FuqGNhh1LxOmVzOlGUriIlOaokOvhaStA==
+
 core-util-is@~1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"
@@ -333,11 +344,7 @@ del@^2.2.2:
     pinkie-promise "^2.0.0"
     rimraf "^2.2.8"
 
-depd@1.1.1:
-  version "1.1.1"
-  resolved "https://registry.yarnpkg.com/depd/-/depd-1.1.1.tgz#5783b4e1c459f06fa5ca27f991f3d06e7a310359"
-
-depd@~1.1.1, depd@~1.1.2:
+depd@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/depd/-/depd-1.1.2.tgz#9bcd52e14c097763e749b274c4346ed2e560b5a9"
 
@@ -432,38 +439,39 @@ express-fileupload@^0.4.0:
     md5 "^2.2.1"
     streamifier "^0.1.1"
 
-express@^4.16.3:
-  version "4.16.3"
-  resolved "https://registry.yarnpkg.com/express/-/express-4.16.3.tgz#6af8a502350db3246ecc4becf6b5a34d22f7ed53"
+express@^4.17.3:
+  version "4.17.3"
+  resolved "https://registry.yarnpkg.com/express/-/express-4.17.3.tgz#f6c7302194a4fb54271b73a1fe7a06478c8f85a1"
+  integrity sha512-yuSQpz5I+Ch7gFrPCk4/c+dIBKlQUxtgwqzph132bsT6qhuzss6I8cLJQz7B3rFblzd6wtcI0ZbGltH/C4LjUg==
   dependencies:
-    accepts "~1.3.5"
+    accepts "~1.3.8"
     array-flatten "1.1.1"
-    body-parser "1.18.2"
-    content-disposition "0.5.2"
+    body-parser "1.19.2"
+    content-disposition "0.5.4"
     content-type "~1.0.4"
-    cookie "0.3.1"
+    cookie "0.4.2"
     cookie-signature "1.0.6"
     debug "2.6.9"
     depd "~1.1.2"
     encodeurl "~1.0.2"
     escape-html "~1.0.3"
     etag "~1.8.1"
-    finalhandler "1.1.1"
+    finalhandler "~1.1.2"
     fresh "0.5.2"
     merge-descriptors "1.0.1"
     methods "~1.1.2"
     on-finished "~2.3.0"
-    parseurl "~1.3.2"
+    parseurl "~1.3.3"
     path-to-regexp "0.1.7"
-    proxy-addr "~2.0.3"
-    qs "6.5.1"
-    range-parser "~1.2.0"
-    safe-buffer "5.1.1"
-    send "0.16.2"
-    serve-static "1.13.2"
-    setprototypeof "1.1.0"
-    statuses "~1.4.0"
-    type-is "~1.6.16"
+    proxy-addr "~2.0.7"
+    qs "6.9.7"
+    range-parser "~1.2.1"
+    safe-buffer "5.2.1"
+    send "0.17.2"
+    serve-static "1.14.2"
+    setprototypeof "1.2.0"
+    statuses "~1.5.0"
+    type-is "~1.6.18"
     utils-merge "1.0.1"
     vary "~1.1.2"
 
@@ -478,16 +486,17 @@ express@^4.16.3:
     node-fetch "^2.1.2"
     socket.io "^2.1.1"
 
-finalhandler@1.1.1:
-  version "1.1.1"
-  resolved "https://registry.yarnpkg.com/finalhandler/-/finalhandler-1.1.1.tgz#eebf4ed840079c83f4249038c9d703008301b105"
+finalhandler@~1.1.2:
+  version "1.1.2"
+  resolved "https://registry.yarnpkg.com/finalhandler/-/finalhandler-1.1.2.tgz#b7e7d000ffd11938d0fdb053506f6ebabe9f587d"
+  integrity sha512-aAWcW57uxVNrQZqFXjITpW3sIUQmHGG3qSb9mUah9MgMC4NeWhNOlNjXEYq3HjRAvL6arUviZGGJsBg6z0zsWA==
   dependencies:
     debug "2.6.9"
     encodeurl "~1.0.2"
     escape-html "~1.0.3"
     on-finished "~2.3.0"
-    parseurl "~1.3.2"
-    statuses "~1.4.0"
+    parseurl "~1.3.3"
+    statuses "~1.5.0"
     unpipe "~1.0.0"
 
 find-up@^1.0.0:
@@ -498,9 +507,10 @@ find-up@^1.0.0:
     path-exists "^2.0.0"
     pinkie-promise "^2.0.0"
 
-forwarded@~0.1.2:
-  version "0.1.2"
-  resolved "https://registry.yarnpkg.com/forwarded/-/forwarded-0.1.2.tgz#98c23dab1175657b8c0573e8ceccd91b0ff18c84"
+forwarded@0.2.0:
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/forwarded/-/forwarded-0.2.0.tgz#2269936428aad4c15c7ebe9779a84bf0b2a81811"
+  integrity sha512-buRG0fpBtRHSTCOASe6hD258tEubFoRLb4ZNA6NxMVHNw2gOcwHo9wyablzMzOA5z9xA9L1KNjk/Nt6MT9aYow==
 
 fresh@0.5.2:
   version "0.5.2"
@@ -568,27 +578,23 @@ hosted-git-info@^2.1.4:
   resolved "https://registry.yarnpkg.com/hosted-git-info/-/hosted-git-info-2.7.1.tgz#97f236977bd6e125408930ff6de3eec6281ec047"
   integrity sha512-7T/BxH19zbcCTa8XkMlbK5lTo1WtgkFi3GvdWEyNuc4Vex7/9Dqbnpsf4JMydcfj9HCg4zUWFTL3Za6lapg5/w==
 
-http-errors@1.6.2:
-  version "1.6.2"
-  resolved "https://registry.yarnpkg.com/http-errors/-/http-errors-1.6.2.tgz#0a002cc85707192a7e7946ceedc11155f60ec736"
-  dependencies:
-    depd "1.1.1"
-    inherits "2.0.3"
-    setprototypeof "1.0.3"
-    statuses ">= 1.3.1 < 2"
-
-http-errors@~1.6.2:
-  version "1.6.3"
-  resolved "https://registry.yarnpkg.com/http-errors/-/http-errors-1.6.3.tgz#8b55680bb4be283a0b5bf4ea2e38580be1d9320d"
+http-errors@1.8.1:
+  version "1.8.1"
+  resolved "https://registry.yarnpkg.com/http-errors/-/http-errors-1.8.1.tgz#7c3f28577cbc8a207388455dbd62295ed07bd68c"
+  integrity sha512-Kpk9Sm7NmI+RHhnj6OIWDI1d6fIoFAtFt9RLaTMRlg/8w49juAStsrBgp0Dp4OdxdVbRIeKhtCUvoi/RuAhO4g==
   dependencies:
     depd "~1.1.2"
-    inherits "2.0.3"
-    setprototypeof "1.1.0"
-    statuses ">= 1.4.0 < 2"
+    inherits "2.0.4"
+    setprototypeof "1.2.0"
+    statuses ">= 1.5.0 < 2"
+    toidentifier "1.0.1"
 
-iconv-lite@0.4.19:
-  version "0.4.19"
-  resolved "https://registry.yarnpkg.com/iconv-lite/-/iconv-lite-0.4.19.tgz#f7468f60135f5e5dad3399c0a81be9a1603a082b"
+iconv-lite@0.4.24:
+  version "0.4.24"
+  resolved "https://registry.yarnpkg.com/iconv-lite/-/iconv-lite-0.4.24.tgz#2022b4b25fbddc21d2f524974a474aafe733908b"
+  integrity sha512-v3MXnZAcvnywkTUEZomIActle7RXXeedOR31wwl7VlyoXO4Qi9arvSenNQWne1TcRwhCL1HwLI21bEqdpj8/rA==
+  dependencies:
+    safer-buffer ">= 2.1.2 < 3"
 
 ignore-walk@^3.0.1:
   version "3.0.1"
@@ -614,18 +620,24 @@ inflight@^1.0.4:
     once "^1.3.0"
     wrappy "1"
 
-inherits@2, inherits@2.0.3, inherits@~2.0.1:
+inherits@2, inherits@~2.0.1:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/inherits/-/inherits-2.0.3.tgz#633c2c83e3da42a502f52466022480f4208261de"
 
+inherits@2.0.4:
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/inherits/-/inherits-2.0.4.tgz#0fa2c64f932917c3433a0ded55363aae37416b7c"
+  integrity sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ==
+
 invert-kv@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/invert-kv/-/invert-kv-1.0.0.tgz#104a8e4aaca6d3d8cd157a8ef8bfab2d7a3ffdb6"
   integrity sha1-EEqOSqym09jNFXqO+L+rLXo//bY=
 
-ipaddr.js@1.6.0:
-  version "1.6.0"
-  resolved "https://registry.yarnpkg.com/ipaddr.js/-/ipaddr.js-1.6.0.tgz#e3fa357b773da619f26e95f049d055c72796f86b"
+ipaddr.js@1.9.1:
+  version "1.9.1"
+  resolved "https://registry.yarnpkg.com/ipaddr.js/-/ipaddr.js-1.9.1.tgz#bff38543eeb8984825079ff3a2a8e6cbd46781b3"
+  integrity sha512-0KI/607xoxSToH7GjN1FfSbLoU0+btTicjsQSWQlh/hZykN8KpmMf7uYwPW3R+akZ6R/w18ZlXSHBYXiYUPO3g==
 
 is-arrayish@^0.2.1:
   version "0.2.1"
@@ -732,19 +744,22 @@ methods@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/methods/-/methods-1.1.2.tgz#5529a4d67654134edcc5266656835b0f851afcee"
 
-mime-db@~1.35.0:
-  version "1.35.0"
-  resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.35.0.tgz#0569d657466491283709663ad379a99b90d9ab47"
+mime-db@1.52.0:
+  version "1.52.0"
+  resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.52.0.tgz#bbabcdc02859f4987301c856e3387ce5ec43bf70"
+  integrity sha512-sPU4uV7dYlvtWJxwwxHD0PuihVNiE7TyAbQ5SWxDCB9mUYvOgroQOwYQQOKPJ8CIbE+1ETVlOoK1UC2nU3gYvg==
 
-mime-types@~2.1.18:
-  version "2.1.19"
-  resolved "https://registry.yarnpkg.com/mime-types/-/mime-types-2.1.19.tgz#71e464537a7ef81c15f2db9d97e913fc0ff606f0"
+mime-types@~2.1.24, mime-types@~2.1.34:
+  version "2.1.35"
+  resolved "https://registry.yarnpkg.com/mime-types/-/mime-types-2.1.35.tgz#381a871b62a734450660ae3deee44813f70d959a"
+  integrity sha512-ZDY+bPm5zTTF+YpCrAU9nK0UgICYPT0QtT1NZWFv4s++TNkcgVaT0g6+4R2uI4MjQjzysHB1zxuWL50hzaeXiw==
   dependencies:
-    mime-db "~1.35.0"
+    mime-db "1.52.0"
 
-mime@1.4.1:
-  version "1.4.1"
-  resolved "https://registry.yarnpkg.com/mime/-/mime-1.4.1.tgz#121f9ebc49e3766f311a76e1fa1c8003c4b03aa6"
+mime@1.6.0:
+  version "1.6.0"
+  resolved "https://registry.yarnpkg.com/mime/-/mime-1.6.0.tgz#32cd9e5c64553bd58d19a568af452acff04981b1"
+  integrity sha512-x0Vn8spI+wuJ1O6S7gnbaQg8Pxh4NNHb7KSINmEWKiPE4RKOplvijn+NkmYmmRgP68mc70j2EbeTFRsrswaQeg==
 
 minimatch@^3.0.4:
   version "3.0.4"
@@ -757,9 +772,15 @@ ms@2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.0.0.tgz#5608aeadfc00be6c2901df5f9861788de0d597c8"
 
-negotiator@0.6.1:
-  version "0.6.1"
-  resolved "https://registry.yarnpkg.com/negotiator/-/negotiator-0.6.1.tgz#2b327184e8992101177b28563fb5e7102acd0ca9"
+ms@2.1.3:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/ms/-/ms-2.1.3.tgz#574c8138ce1d2b5861f0b44579dbadd60c6615b2"
+  integrity sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==
+
+negotiator@0.6.3:
+  version "0.6.3"
+  resolved "https://registry.yarnpkg.com/negotiator/-/negotiator-0.6.3.tgz#58e323a72fedc0d6f9cd4d31fe49f51479590ccd"
+  integrity sha512-+EUsqGPLsM+j/zdChZjsnX51g4XrHFOIXwfnCVPGlQk/k5giakcKsuxCObBRu6DSm9opw/O6slWbJdghQM4bBg==
 
 nice-try@^1.0.4:
   version "1.0.4"
@@ -850,9 +871,10 @@ parseuri@0.0.5:
   dependencies:
     better-assert "~1.0.0"
 
-parseurl@~1.3.2:
-  version "1.3.2"
-  resolved "https://registry.yarnpkg.com/parseurl/-/parseurl-1.3.2.tgz#fc289d4ed8993119460c156253262cdc8de65bf3"
+parseurl@~1.3.3:
+  version "1.3.3"
+  resolved "https://registry.yarnpkg.com/parseurl/-/parseurl-1.3.3.tgz#9da19e7bee8d12dff0513ed5b76957793bc2e8d4"
+  integrity sha512-CiyeOxFT/JZyN5m0z9PfXw4SCBJ6Sygz1Dpl0wqjlhDEGGBP1GnsUVEL0p63hoG1fcj3fHynXi9NYO4nWOL+qQ==
 
 path-exists@^2.0.0:
   version "2.1.0"
@@ -928,36 +950,40 @@ protobufjs@~6.8.6:
     "@types/node" "^10.1.0"
     long "^4.0.0"
 
-proxy-addr@~2.0.3:
-  version "2.0.3"
-  resolved "https://registry.yarnpkg.com/proxy-addr/-/proxy-addr-2.0.3.tgz#355f262505a621646b3130a728eb647e22055341"
+proxy-addr@~2.0.7:
+  version "2.0.7"
+  resolved "https://registry.yarnpkg.com/proxy-addr/-/proxy-addr-2.0.7.tgz#f19fe69ceab311eeb94b42e70e8c2070f9ba1025"
+  integrity sha512-llQsMLSUDUPT44jdrU/O37qlnifitDP+ZwrmmZcoSKyLKvtZxpyV0n2/bD/N4tBAAZ/gJEdZU7KMraoK1+XYAg==
   dependencies:
-    forwarded "~0.1.2"
-    ipaddr.js "1.6.0"
+    forwarded "0.2.0"
+    ipaddr.js "1.9.1"
 
 punycode@1.3.2:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.3.2.tgz#9653a036fb7c1ee42342f2325cceefea3926c48d"
 
-qs@6.5.1:
-  version "6.5.1"
-  resolved "https://registry.yarnpkg.com/qs/-/qs-6.5.1.tgz#349cdf6eef89ec45c12d7d5eb3fc0c870343a6d8"
+qs@6.9.7:
+  version "6.9.7"
+  resolved "https://registry.yarnpkg.com/qs/-/qs-6.9.7.tgz#4610846871485e1e048f44ae3b94033f0e675afe"
+  integrity sha512-IhMFgUmuNpyRfxA90umL7ByLlgRXu6tIfKPpF5TmcfRLlLCckfP/g3IQmju6jjpu+Hh8rA+2p6A27ZSPOOHdKw==
 
 querystring@0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/querystring/-/querystring-0.2.0.tgz#b209849203bb25df820da756e747005878521620"
 
-range-parser@~1.2.0:
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/range-parser/-/range-parser-1.2.0.tgz#f49be6b487894ddc40dcc94a322f611092e00d5e"
+range-parser@~1.2.1:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/range-parser/-/range-parser-1.2.1.tgz#3cf37023d199e1c24d1a55b84800c2f3e6468031"
+  integrity sha512-Hrgsx+orqoygnmhFbKaHE6c296J+HTAQXoxEF6gNupROmmGJRoyzfG3ccAveqCBrwr/2yxQ5BVd/GTl5agOwSg==
 
-raw-body@2.3.2:
-  version "2.3.2"
-  resolved "https://registry.yarnpkg.com/raw-body/-/raw-body-2.3.2.tgz#bcd60c77d3eb93cde0050295c3f379389bc88f89"
+raw-body@2.4.3:
+  version "2.4.3"
+  resolved "https://registry.yarnpkg.com/raw-body/-/raw-body-2.4.3.tgz#8f80305d11c2a0a545c2d9d89d7a0286fcead43c"
+  integrity sha512-UlTNLIcu0uzb4D2f4WltY6cVjLi+/jEN4lgEUj3E04tpMDpUlkBo/eSn6zou9hum2VMNpCCUone0O0WeJim07g==
   dependencies:
-    bytes "3.0.0"
-    http-errors "1.6.2"
-    iconv-lite "0.4.19"
+    bytes "3.1.2"
+    http-errors "1.8.1"
+    iconv-lite "0.4.24"
     unpipe "1.0.0"
 
 read-pkg-up@^1.0.1:
@@ -1010,14 +1036,20 @@ rimraf@^2.2.8:
   dependencies:
     glob "^7.1.3"
 
-safe-buffer@5.1.1:
-  version "5.1.1"
-  resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.1.1.tgz#893312af69b2123def71f57889001671eeb2c853"
-
 safe-buffer@5.1.2, safe-buffer@~5.1.0:
   version "5.1.2"
   resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.1.2.tgz#991ec69d296e0313747d59bdfd2b745c35f8828d"
 
+safe-buffer@5.2.1:
+  version "5.2.1"
+  resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.2.1.tgz#1eaf9fa9bdb1fdd4ec75f58f9cdb4e6b7827eec6"
+  integrity sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ==
+
+"safer-buffer@>= 2.1.2 < 3":
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/safer-buffer/-/safer-buffer-2.1.2.tgz#44fa161b0187b9549dd84bb91802f9bd8385cd6a"
+  integrity sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg==
+
 seedrandom@~2.4.3:
   version "2.4.3"
   resolved "https://registry.yarnpkg.com/seedrandom/-/seedrandom-2.4.3.tgz#2438504dad33917314bff18ac4d794f16d6aaecc"
@@ -1031,9 +1063,10 @@ semver@^5.5.0:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.0.tgz#dc4bbc7a6ca9d916dee5d43516f0092b58f7b8ab"
 
-send@0.16.2:
-  version "0.16.2"
-  resolved "https://registry.yarnpkg.com/send/-/send-0.16.2.tgz#6ecca1e0f8c156d141597559848df64730a6bbc1"
+send@0.17.2:
+  version "0.17.2"
+  resolved "https://registry.yarnpkg.com/send/-/send-0.17.2.tgz#926622f76601c41808012c8bf1688fe3906f7820"
+  integrity sha512-UJYB6wFSJE3G00nEivR5rgWp8c2xXvJ3OPWPhmuteU0IKj8nKbG3DrjiOmLwpnHGYWAVwA69zmTm++YG0Hmwww==
   dependencies:
     debug "2.6.9"
     depd "~1.1.2"
@@ -1042,34 +1075,32 @@ send@0.16.2:
     escape-html "~1.0.3"
     etag "~1.8.1"
     fresh "0.5.2"
-    http-errors "~1.6.2"
-    mime "1.4.1"
-    ms "2.0.0"
+    http-errors "1.8.1"
+    mime "1.6.0"
+    ms "2.1.3"
     on-finished "~2.3.0"
-    range-parser "~1.2.0"
-    statuses "~1.4.0"
+    range-parser "~1.2.1"
+    statuses "~1.5.0"
 
-serve-static@1.13.2:
-  version "1.13.2"
-  resolved "https://registry.yarnpkg.com/serve-static/-/serve-static-1.13.2.tgz#095e8472fd5b46237db50ce486a43f4b86c6cec1"
+serve-static@1.14.2:
+  version "1.14.2"
+  resolved "https://registry.yarnpkg.com/serve-static/-/serve-static-1.14.2.tgz#722d6294b1d62626d41b43a013ece4598d292bfa"
+  integrity sha512-+TMNA9AFxUEGuC0z2mevogSnn9MXKb4fa7ngeRMJaaGv8vTwnIEkKi+QGvPt33HSnf8pRS+WGM0EbMtCJLKMBQ==
   dependencies:
     encodeurl "~1.0.2"
     escape-html "~1.0.3"
-    parseurl "~1.3.2"
-    send "0.16.2"
+    parseurl "~1.3.3"
+    send "0.17.2"
 
 set-blocking@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/set-blocking/-/set-blocking-2.0.0.tgz#045f9782d011ae9a6803ddd382b24392b3d890f7"
   integrity sha1-BF+XgtARrppoA93TgrJDkrPYkPc=
 
-setprototypeof@1.0.3:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/setprototypeof/-/setprototypeof-1.0.3.tgz#66567e37043eeb4f04d91bd658c0cbefb55b8e04"
-
-setprototypeof@1.1.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/setprototypeof/-/setprototypeof-1.1.0.tgz#d0bd85536887b6fe7c0d818cb962d9d91c54e656"
+setprototypeof@1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/setprototypeof/-/setprototypeof-1.2.0.tgz#66c9a24a73f9fc28cbe66b09fed3d33dcaf1b424"
+  integrity sha512-E5LDX7Wrp85Kil5bhZv46j8jOeboKq5JMmYM3gVGdGH8xFpPWXUMsNrlODCrkoxMEeNi/XZIwuRvY4XNwYMJpw==
 
 shebang-command@^1.2.0:
   version "1.2.0"
@@ -1149,13 +1180,10 @@ spdx-license-ids@^3.0.0:
   resolved "https://registry.yarnpkg.com/spdx-license-ids/-/spdx-license-ids-3.0.4.tgz#75ecd1a88de8c184ef015eafb51b5b48bfd11bb1"
   integrity sha512-7j8LYJLeY/Yb6ACbQ7F76qy5jHkp0U6jgBfJsk97bwWlVUnUWsAgpyaCvo17h0/RQGnQ036tVDomiwoI4pDkQA==
 
-"statuses@>= 1.3.1 < 2", "statuses@>= 1.4.0 < 2":
+"statuses@>= 1.5.0 < 2", statuses@~1.5.0:
   version "1.5.0"
   resolved "https://registry.yarnpkg.com/statuses/-/statuses-1.5.0.tgz#161c7dac177659fd9811f43771fa99381478628c"
-
-statuses@~1.4.0:
-  version "1.4.0"
-  resolved "https://registry.yarnpkg.com/statuses/-/statuses-1.4.0.tgz#bb73d446da2796106efcc1b601a253d6c46bd087"
+  integrity sha512-OpZ3zP+jT1PI7I8nemJX4AKmAX070ZkYPVWV/AaKTJl+tXCTGyVdC1a4SL8RUQYEwk/f34ZX8UTykN68FwrqAA==
 
 streamifier@^0.1.1:
   version "0.1.1"
@@ -1200,12 +1228,18 @@ to-array@0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/to-array/-/to-array-0.1.4.tgz#17e6c11f73dd4f3d74cda7a4ff3238e9ad9bf890"
 
-type-is@~1.6.15, type-is@~1.6.16:
-  version "1.6.16"
-  resolved "https://registry.yarnpkg.com/type-is/-/type-is-1.6.16.tgz#f89ce341541c672b25ee7ae3c73dee3b2be50194"
+toidentifier@1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/toidentifier/-/toidentifier-1.0.1.tgz#3be34321a88a820ed1bd80dfaa33e479fbb8dd35"
+  integrity sha512-o5sSPKEkg/DIQNmH43V0/uerLrpzVedkUh8tGNvaeXpfpuwjKenlSox/2O/BTlZUtEe+JG7s5YhEz608PlAHRA==
+
+type-is@~1.6.18:
+  version "1.6.18"
+  resolved "https://registry.yarnpkg.com/type-is/-/type-is-1.6.18.tgz#4e552cd05df09467dcbc4ef739de89f2cf37c131"
+  integrity sha512-TkRKr9sUTxEH8MdfuCSP7VizJyzRNMjj2J2do2Jr3Kym598JVdEksuzPQCnlFPW4ky9Q+iA+ma9BGm06XQBy8g==
   dependencies:
     media-typer "0.3.0"
-    mime-types "~2.1.18"
+    mime-types "~2.1.24"
 
 ultron@~1.1.0:
   version "1.1.1"