diff --git a/package-lock.json b/package-lock.json
index 98cf8ec..988b6fa 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4,6 +4,20 @@
 	"lockfileVersion": 1,
 	"requires": true,
 	"dependencies": {
+		"accepts": {
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+			"resolved": "https://registry.npmjs.org/accepts/-/accepts-1.3.7.tgz",
+			"integrity": "sha512-Il80Qs2WjYlJIBNzNkK6KYqlVMTbZLXgHx2oT0pU/fjRHyEp+PEfEPY0R3WCwAGVOtauxh1hOxNgIf5bv7dQpA==",
+			"requires": {
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+				"negotiator": "0.6.2"
+			}
+		},
+		"after": {
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+			"resolved": "https://registry.npmjs.org/after/-/after-0.8.2.tgz",
+			"integrity": "sha1-/ts5T58OAqqXaOcCvaI7UF+ufh8="
+		},
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 			"resolved": "https://registry.npmjs.org/ajv/-/ajv-6.10.2.tgz",
@@ -16,6 +30,11 @@
 				"uri-js": "^4.2.2"
 			}
 		},
+		"arraybuffer.slice": {
+			"version": "0.0.7",
+			"resolved": "https://registry.npmjs.org/arraybuffer.slice/-/arraybuffer.slice-0.0.7.tgz",
+			"integrity": "sha512-wGUIVQXuehL5TCqQun8OW81jGzAWycqzFF8lFp+GOM5BXLYj3bKNsYC4daB7n6XjCqxQA/qgTJ+8ANR3acjrog=="
+		},
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 			"resolved": "https://registry.npmjs.org/asn1/-/asn1-0.2.4.tgz",
@@ -28,7 +47,8 @@
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-			"integrity": "sha1-8S4PPF13sLHN2RRpQuTpbB5N1SU="
+			"integrity": "sha1-8S4PPF13sLHN2RRpQuTpbB5N1SU=",
+			"optional": true
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@@ -53,6 +73,21 @@
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 			"optional": true
 		},
+		"backo2": {
+			"version": "1.0.2",
+			"resolved": "https://registry.npmjs.org/backo2/-/backo2-1.0.2.tgz",
+			"integrity": "sha1-MasayLEpNjRj41s+u2n038+6eUc="
+		},
+		"base64-arraybuffer": {
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+			"resolved": "https://registry.npmjs.org/base64-arraybuffer/-/base64-arraybuffer-0.1.4.tgz",
+			"integrity": "sha1-mBjHngWbE1X5fgQooBfIOOkLqBI="
+		},
+		"base64id": {
+			"version": "2.0.0",
+			"resolved": "https://registry.npmjs.org/base64id/-/base64id-2.0.0.tgz",
+			"integrity": "sha512-lGe34o6EHj9y3Kts9R4ZYs/Gr+6N7MCaMlIFA3F1R2O5/m7K06AxfSeO5530PEERE6/WyEg3lsuyw4GHlPZHog=="
+		},
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@@ -62,6 +97,11 @@
 				"tweetnacl": "^0.14.3"
 			}
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+		"blob": {
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+			"resolved": "https://registry.npmjs.org/blob/-/blob-0.0.5.tgz",
+			"integrity": "sha512-gaqbzQPqOoamawKg0LGVd7SzLgXS+JH61oWprSLH+P+abTczqJbhTR8CmJ2u9/bUYNmHTGJx/UEmn6doAvvuig=="
+		},
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+			"optional": true,
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@@ -97,6 +138,21 @@
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 			"integrity": "sha1-+mihT2qUXVTbvlDYzbMyDp47GgY="
 		},
+		"component-bind": {
+			"version": "1.0.0",
+			"resolved": "https://registry.npmjs.org/component-bind/-/component-bind-1.0.0.tgz",
+			"integrity": "sha1-AMYIq33Nk4l8AAllGx06jh5zu9E="
+		},
+		"component-emitter": {
+			"version": "1.3.0",
+			"resolved": "https://registry.npmjs.org/component-emitter/-/component-emitter-1.3.0.tgz",
+			"integrity": "sha512-Rd3se6QB+sO1TwqZjscQrurpEPIfO0/yYnSin6Q/rD3mOutHvUrCAhJub3r90uNb+SESBuE0QYoB90YdfatsRg=="
+		},
+		"component-inherit": {
+			"version": "0.0.3",
+			"resolved": "https://registry.npmjs.org/component-inherit/-/component-inherit-0.0.3.tgz",
+			"integrity": "sha1-ZF/ErfWLcrZJ1crmUTVhnbJv8UM="
+		},
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 			"resolved": "https://registry.npmjs.org/connect/-/connect-2.7.2.tgz",
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-			"integrity": "sha1-3zrhmayt+31ECqrgsp4icrJOxhk="
+			"integrity": "sha1-3zrhmayt+31ECqrgsp4icrJOxhk=",
+			"optional": true
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 			"version": "1.0.2",
@@ -168,6 +225,71 @@
 				"safer-buffer": "^2.1.0"
 			}
 		},
+		"engine.io": {
+			"version": "3.5.0",
+			"resolved": "https://registry.npmjs.org/engine.io/-/engine.io-3.5.0.tgz",
+			"integrity": "sha512-21HlvPUKaitDGE4GXNtQ7PLP0Sz4aWLddMPw2VTyFz1FVZqu/kZsJUO8WNpKuE/OCL7nkfRaOui2ZCJloGznGA==",
+			"requires": {
+				"accepts": "~1.3.4",
+				"base64id": "2.0.0",
+				"cookie": "~0.4.1",
+				"debug": "~4.1.0",
+				"engine.io-parser": "~2.2.0",
+				"ws": "~7.4.2"
+			},
+			"dependencies": {
+				"cookie": {
+					"version": "0.4.1",
+					"resolved": "https://registry.npmjs.org/cookie/-/cookie-0.4.1.tgz",
+					"integrity": "sha512-ZwrFkGJxUR3EIoXtO+yVE69Eb7KlixbaeAWfBQB9vVsNn/o+Yw69gBWSSDK825hQNdN+wF8zELf3dFNl/kxkUA=="
+				}
+			}
+		},
+		"engine.io-client": {
+			"version": "3.5.0",
+			"resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-3.5.0.tgz",
+			"integrity": "sha512-12wPRfMrugVw/DNyJk34GQ5vIVArEcVMXWugQGGuw2XxUSztFNmJggZmv8IZlLyEdnpO1QB9LkcjeWewO2vxtA==",
+			"requires": {
+				"component-emitter": "~1.3.0",
+				"component-inherit": "0.0.3",
+				"debug": "~3.1.0",
+				"engine.io-parser": "~2.2.0",
+				"has-cors": "1.1.0",
+				"indexof": "0.0.1",
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+				"xmlhttprequest-ssl": "~1.5.4",
+				"yeast": "0.1.2"
+			},
+			"dependencies": {
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+					"version": "3.1.0",
+					"resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
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+					"requires": {
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+					}
+				},
+				"ms": {
+					"version": "2.0.0",
+					"resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
+					"integrity": "sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g="
+				}
+			}
+		},
+		"engine.io-parser": {
+			"version": "2.2.1",
+			"resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-2.2.1.tgz",
+			"integrity": "sha512-x+dN/fBH8Ro8TFwJ+rkB2AmuVw9Yu2mockR/p3W8f8YtExwFgDvBDi0GWyb4ZLkpahtDGZgtr3zLovanJghPqg==",
+			"requires": {
+				"after": "0.8.2",
+				"arraybuffer.slice": "~0.0.7",
+				"base64-arraybuffer": "0.1.4",
+				"blob": "0.0.5",
+				"has-binary2": "~1.0.2"
+			}
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@@ -195,7 +317,8 @@
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-			"integrity": "sha1-lpGEQOMEGnpBT4xS48V06zw+HgU="
+			"integrity": "sha1-lpGEQOMEGnpBT4xS48V06zw+HgU=",
+			"optional": true
 		},
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@@ -282,6 +405,19 @@
 				"har-schema": "^2.0.0"
 			}
 		},
+		"has-binary2": {
+			"version": "1.0.3",
+			"resolved": "https://registry.npmjs.org/has-binary2/-/has-binary2-1.0.3.tgz",
+			"integrity": "sha512-G1LWKhDSvhGeAQ8mPVQlqNcOB2sJdwATtZKl2pDKKHfpf/rYj24lkinxf69blJbnsvtqqNU+L3SL50vzZhXOnw==",
+			"requires": {
+				"isarray": "2.0.1"
+			}
+		},
+		"has-cors": {
+			"version": "1.1.0",
+			"resolved": "https://registry.npmjs.org/has-cors/-/has-cors-1.1.0.tgz",
+			"integrity": "sha1-XkdHk/fqmEPRu5nCPu9J/xJv/zk="
+		},
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@@ -293,6 +429,11 @@
 				"sshpk": "^1.7.0"
 			}
 		},
+		"indexof": {
+			"version": "0.0.1",
+			"resolved": "https://registry.npmjs.org/indexof/-/indexof-0.0.1.tgz",
+			"integrity": "sha1-gtwzbSMrkGIXnQWrMpOmYFn9Q10="
+		},
 		"inherits": {
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 			"resolved": "https://registry.npmjs.org/inherits/-/inherits-1.0.2.tgz",
@@ -304,6 +445,11 @@
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 			"optional": true
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+			"version": "2.0.1",
+			"resolved": "https://registry.npmjs.org/isarray/-/isarray-2.0.1.tgz",
+			"integrity": "sha1-o32U7ZzaLVmGXJ92/llu4fM4dB4="
+		},
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 			"resolved": "https://registry.npmjs.org/isstream/-/isstream-0.1.2.tgz",
@@ -349,7 +495,8 @@
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-			"integrity": "sha1-peZUwuWi3rXyAdls77yoDA7y9RM="
+			"integrity": "sha1-peZUwuWi3rXyAdls77yoDA7y9RM=",
+			"optional": true
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@@ -507,12 +654,27 @@
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 		},
+		"negotiator": {
+			"version": "0.6.2",
+			"resolved": "https://registry.npmjs.org/negotiator/-/negotiator-0.6.2.tgz",
+			"integrity": "sha512-hZXc7K2e+PgeI1eDBe/10Ard4ekbfrrqG8Ep+8Jmf4JID2bNg7NvCPOZN+kfF574pFQI7mum2AUqDidoKqcTOw=="
+		},
 		"oauth-sign": {
 			"version": "0.9.0",
 			"resolved": "https://registry.npmjs.org/oauth-sign/-/oauth-sign-0.9.0.tgz",
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 			"optional": true
 		},
+		"parseqs": {
+			"version": "0.0.6",
+			"resolved": "https://registry.npmjs.org/parseqs/-/parseqs-0.0.6.tgz",
+			"integrity": "sha512-jeAGzMDbfSHHA091hr0r31eYfTig+29g3GKKE/PPbEQ65X0lmMwlEoqmhzu0iztID5uJpZsFlUPDP8ThPL7M8w=="
+		},
+		"parseuri": {
+			"version": "0.0.6",
+			"resolved": "https://registry.npmjs.org/parseuri/-/parseuri-0.0.6.tgz",
+			"integrity": "sha512-AUjen8sAkGgao7UyCX6Ahv0gIK2fABKmYjvP4xmy5JaKvcbTRueIqIPHLAfq30xJddqSE033IOMUSOMCcK3Sow=="
+		},
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@@ -585,12 +747,14 @@
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+			"integrity": "sha512-fZEwUGbVl7kouZs1jCdMLdt95hdIv0ZeHg6L7qPeciMZhZ+/gdesW4wgTARkrFWEpspjEATAzUGPG8N2jJiwbg==",
+			"optional": true
 		},
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 			"version": "2.1.2",
 			"resolved": "https://registry.npmjs.org/safer-buffer/-/safer-buffer-2.1.2.tgz",
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+			"integrity": "sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg==",
+			"optional": true
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@@ -609,9 +773,82 @@
 			"integrity": "sha1-P/IfGYytIXX587eBhT/ZTQ0ZtZA="
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-			"integrity": "sha1-Bm3OVE7r2VNqYf4I/0Ti47v9ghE="
+			"version": "2.4.0",
+			"resolved": "https://registry.npmjs.org/socket.io/-/socket.io-2.4.0.tgz",
+			"integrity": "sha512-9UPJ1UTvKayuQfVv2IQ3k7tCQC/fboDyIK62i99dAQIyHKaBsNdTpwHLgKJ6guRWxRtC9H+138UwpaGuQO9uWQ==",
+			"requires": {
+				"debug": "~4.1.0",
+				"engine.io": "~3.5.0",
+				"has-binary2": "~1.0.2",
+				"socket.io-adapter": "~1.1.0",
+				"socket.io-client": "2.4.0",
+				"socket.io-parser": "~3.4.0"
+			}
+		},
+		"socket.io-adapter": {
+			"version": "1.1.2",
+			"resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-1.1.2.tgz",
+			"integrity": "sha512-WzZRUj1kUjrTIrUKpZLEzFZ1OLj5FwLlAFQs9kuZJzJi5DKdU7FsWc36SNmA8iDOtwBQyT8FkrriRM8vXLYz8g=="
+		},
+		"socket.io-client": {
+			"version": "2.4.0",
+			"resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-2.4.0.tgz",
+			"integrity": "sha512-M6xhnKQHuuZd4Ba9vltCLT9oa+YvTsP8j9NcEiLElfIg8KeYPyhWOes6x4t+LTAC8enQbE/995AdTem2uNyKKQ==",
+			"requires": {
+				"backo2": "1.0.2",
+				"component-bind": "1.0.0",
+				"component-emitter": "~1.3.0",
+				"debug": "~3.1.0",
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+				"has-binary2": "~1.0.2",
+				"indexof": "0.0.1",
+				"parseqs": "0.0.6",
+				"parseuri": "0.0.6",
+				"socket.io-parser": "~3.3.0",
+				"to-array": "0.1.4"
+			},
+			"dependencies": {
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+					"version": "3.1.0",
+					"resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
+					"integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+					"requires": {
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+					}
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+				"ms": {
+					"version": "2.0.0",
+					"resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
+					"integrity": "sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g="
+				},
+				"socket.io-parser": {
+					"version": "3.3.2",
+					"resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-3.3.2.tgz",
+					"integrity": "sha512-FJvDBuOALxdCI9qwRrO/Rfp9yfndRtc1jSgVgV8FDraihmSP/MLGD5PEuJrNfjALvcQ+vMDM/33AWOYP/JSjDg==",
+					"requires": {
+						"component-emitter": "~1.3.0",
+						"debug": "~3.1.0",
+						"isarray": "2.0.1"
+					}
+				}
+			}
+		},
+		"socket.io-parser": {
+			"version": "3.4.1",
+			"resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-3.4.1.tgz",
+			"integrity": "sha512-11hMgzL+WCLWf1uFtHSNvliI++tcRUWdoeYuwIl+Axvwy9z2gQM+7nJyN3STj1tLj5JyIUH8/gpDGxzAlDdi0A==",
+			"requires": {
+				"component-emitter": "1.2.1",
+				"debug": "~4.1.0",
+				"isarray": "2.0.1"
+			},
+			"dependencies": {
+				"component-emitter": {
+					"version": "1.2.1",
+					"resolved": "https://registry.npmjs.org/component-emitter/-/component-emitter-1.2.1.tgz",
+					"integrity": "sha1-E3kY1teCg/ffemt8WmPhQOaUJeY="
+				}
+			}
 		},
 		"sshpk": {
 			"version": "1.16.1",
@@ -630,6 +867,11 @@
 				"tweetnacl": "~0.14.0"
 			}
 		},
+		"to-array": {
+			"version": "0.1.4",
+			"resolved": "https://registry.npmjs.org/to-array/-/to-array-0.1.4.tgz",
+			"integrity": "sha1-F+bBH3PdTz10zaek/zI46a2b+JA="
+		},
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@@ -660,7 +902,8 @@
 		"tweetnacl": {
 			"version": "0.14.5",
 			"resolved": "https://registry.npmjs.org/tweetnacl/-/tweetnacl-0.14.5.tgz",
-			"integrity": "sha1-WuaBd/GS1EViadEIr6k/+HQ/T2Q="
+			"integrity": "sha1-WuaBd/GS1EViadEIr6k/+HQ/T2Q=",
+			"optional": true
 		},
 		"uglify-js": {
 			"version": "1.2.5",
@@ -698,11 +941,26 @@
 				"extsprintf": "^1.2.0"
 			}
 		},
+		"ws": {
+			"version": "7.4.2",
+			"resolved": "https://registry.npmjs.org/ws/-/ws-7.4.2.tgz",
+			"integrity": "sha512-T4tewALS3+qsrpGI/8dqNMLIVdq/g/85U98HPMa6F0m6xTbvhXU6RCQLqPH3+SlomNV/LdY6RXEbBpMH6EOJnA=="
+		},
+		"xmlhttprequest-ssl": {
+			"version": "1.5.5",
+			"resolved": "https://registry.npmjs.org/xmlhttprequest-ssl/-/xmlhttprequest-ssl-1.5.5.tgz",
+			"integrity": "sha1-wodrBhaKrcQOV9l+gRkayPQ5iz4="
+		},
 		"ycssmin": {
 			"version": "1.0.1",
 			"resolved": "https://registry.npmjs.org/ycssmin/-/ycssmin-1.0.1.tgz",
 			"integrity": "sha1-fN3o23jPqwDSkBw7IwHjBPr03xY=",
 			"optional": true
+		},
+		"yeast": {
+			"version": "0.1.2",
+			"resolved": "https://registry.npmjs.org/yeast/-/yeast-0.1.2.tgz",
+			"integrity": "sha1-AI4G2AlDIMNy28L47XagymyKxBk="
 		}
 	}
 }
diff --git a/package.json b/package.json
index 7c7a83f..fd300d3 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,7 @@
 		"url": "git@github.com:lorenyu/nurd.git"
 	},
 	"dependencies": {
-		"socket.io": "0.6.x",
+		"socket.io": "2.4.x",
 		"underscore": "1.4.x",
 		"jade": "0.28.2",
 		"jade-browser": "0.0.x",