diff --git a/README.md b/README.md
index c50566cc9..cb8821b1e 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Key features
 * Two-Factor Authentication support
 * ServiceWorker support
 * Web API for third-party applications
-* No ads
+* ActivityPub compatible
 
 and more! You can touch with your own eyes at https://misskey.xyz/.
 
diff --git a/locales/ja.yml b/locales/ja.yml
index f826b1b6c..fd140ecc3 100644
--- a/locales/ja.yml
+++ b/locales/ja.yml
@@ -147,7 +147,7 @@ common:
       available: "利用できます"
       unavailable: "既に利用されています"
       error: "通信エラー"
-      invalid-format: "a~z、A~Z、0~9、-(ハイフン)が使えます"
+      invalid-format: "a~z、A~Z、0~9、_が使えます"
       too-short: "3文字以上でお願いします！"
       too-long: "20文字以内でお願いします"
       password: "パスワード"
diff --git a/package.json b/package.json
index d9ed80b47..eb65e41db 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
 	"name": "misskey",
 	"author": "syuilo <i@syuilo.com>",
 	"version": "0.0.4224",
+	"codename": "nighthike",
 	"license": "MIT",
 	"description": "A miniblog-based SNS",
 	"bugs": "https://github.com/syuilo/misskey/issues",
@@ -15,6 +16,7 @@
 		"swagger": "node ./swagger.js",
 		"build": "node --max_old_space_size=16384 ./node_modules/webpack/bin/webpack.js && gulp build",
 		"webpack": "node --max_old_space_size=16384 ./node_modules/webpack/bin/webpack.js",
+		"watch": "node --max_old_space_size=16384 ./node_modules/webpack/bin/webpack.js --watch",
 		"gulp": "gulp build",
 		"rebuild": "gulp rebuild",
 		"clean": "gulp clean",
@@ -44,11 +46,11 @@
 		"@types/express": "4.11.1",
 		"@types/gm": "1.17.33",
 		"@types/gulp": "3.8.36",
-		"@types/gulp-htmlmin": "1.3.31",
-		"@types/gulp-mocha": "0.0.31",
+		"@types/gulp-htmlmin": "1.3.32",
+		"@types/gulp-mocha": "0.0.32",
 		"@types/gulp-rename": "0.0.33",
 		"@types/gulp-replace": "0.0.31",
-		"@types/gulp-uglify": "3.0.4",
+		"@types/gulp-uglify": "3.0.5",
 		"@types/gulp-util": "3.0.34",
 		"@types/inquirer": "0.0.38",
 		"@types/is-root": "1.0.0",
@@ -56,13 +58,13 @@
 		"@types/js-yaml": "3.10.1",
 		"@types/license-checker": "15.0.0",
 		"@types/mkdirp": "0.5.2",
-		"@types/mocha": "2.2.48",
-		"@types/mongodb": "3.0.8",
+		"@types/mocha": "5.0.0",
+		"@types/mongodb": "3.0.9",
 		"@types/monk": "6.0.0",
 		"@types/morgan": "1.7.35",
 		"@types/ms": "0.7.30",
 		"@types/multer": "1.3.6",
-		"@types/node": "9.4.7",
+		"@types/node": "9.6.0",
 		"@types/proxy-addr": "2.0.0",
 		"@types/pug": "2.0.4",
 		"@types/qrcode": "0.8.1",
@@ -76,13 +78,13 @@
 		"@types/speakeasy": "2.0.2",
 		"@types/tmp": "0.0.33",
 		"@types/uuid": "3.4.3",
-		"@types/webpack": "4.1.1",
+		"@types/webpack": "4.1.2",
 		"@types/webpack-stream": "3.2.10",
 		"@types/websocket": "0.0.38",
 		"@types/ws": "4.0.1",
 		"accesses": "2.5.0",
 		"animejs": "2.2.0",
-		"autosize": "4.0.0",
+		"autosize": "4.0.1",
 		"autwh": "0.0.1",
 		"bcryptjs": "2.4.3",
 		"body-parser": "1.18.2",
@@ -114,7 +116,7 @@
 		"fuckadblock": "3.2.1",
 		"gm": "1.23.1",
 		"gulp": "3.9.1",
-		"gulp-cssnano": "2.1.2",
+		"gulp-cssnano": "2.1.3",
 		"gulp-htmlmin": "4.0.0",
 		"gulp-imagemin": "4.1.0",
 		"gulp-mocha": "5.0.0",
@@ -130,25 +132,25 @@
 		"hard-source-webpack-plugin": "0.6.4",
 		"highlight.js": "9.12.0",
 		"html-minifier": "3.5.12",
-		"inquirer": "5.1.0",
+		"inquirer": "5.2.0",
 		"is-root": "2.0.0",
-		"is-url": "1.2.3",
+		"is-url": "1.2.4",
 		"js-yaml": "3.11.0",
-		"jsdom": "^11.6.2",
+		"jsdom": "11.6.2",
 		"license-checker": "18.0.0",
 		"loader-utils": "1.1.0",
 		"mecab-async": "0.1.2",
 		"mkdirp": "0.5.1",
-		"mocha": "5.0.4",
+		"mocha": "5.0.5",
 		"moji": "0.5.1",
-		"mongodb": "3.0.4",
+		"mongodb": "3.0.5",
 		"monk": "6.0.5",
 		"morgan": "1.9.0",
 		"ms": "2.1.1",
 		"multer": "1.3.0",
-		"nan": "^2.10.0",
-		"node-sass": "4.7.2",
-		"node-sass-json-importer": "3.1.5",
+		"nan": "2.10.0",
+		"node-sass": "4.8.3",
+		"node-sass-json-importer": "3.1.6",
 		"nprogress": "0.2.0",
 		"object-assign-deep": "0.3.1",
 		"on-build-webpack": "0.1.0",
@@ -157,7 +159,7 @@
 		"prominence": "0.2.0",
 		"proxy-addr": "2.0.3",
 		"pug": "2.0.3",
-		"punycode": "^2.1.0",
+		"punycode": "2.1.0",
 		"qrcode": "1.2.0",
 		"ratelimiter": "3.0.3",
 		"recaptcha-promise": "0.1.3",
@@ -181,10 +183,10 @@
 		"tcp-port-used": "0.1.2",
 		"textarea-caret": "3.1.0",
 		"tmp": "0.0.33",
-		"ts-loader": "4.0.1",
+		"ts-loader": "4.1.0",
 		"ts-node": "5.0.1",
 		"tslint": "5.9.1",
-		"typescript": "2.7.2",
+		"typescript": "2.8.1",
 		"typescript-eslint-parser": "14.0.0",
 		"uglify-es": "3.3.9",
 		"url-loader": "1.0.1",
@@ -195,13 +197,13 @@
 		"vue-cropperjs": "2.2.0",
 		"vue-js-modal": "1.3.12",
 		"vue-json-tree-view": "2.1.3",
-		"vue-loader": "14.2.1",
+		"vue-loader": "14.2.2",
 		"vue-router": "3.0.1",
 		"vue-template-compiler": "2.5.16",
 		"vuedraggable": "2.16.0",
 		"web-push": "3.3.0",
-		"webfinger.js": "^2.6.6",
-		"webpack": "4.2.0",
+		"webfinger.js": "2.6.6",
+		"webpack": "4.3.0",
 		"webpack-cli": "2.0.13",
 		"webpack-replace-loader": "1.3.0",
 		"websocket": "1.0.25",
diff --git a/src/api/bot/core.ts b/src/api/bot/core.ts
index 77a68aaee..d6706e9a1 100644
--- a/src/api/bot/core.ts
+++ b/src/api/bot/core.ts
@@ -67,7 +67,7 @@ export default class BotCore extends EventEmitter {
 			return await this.context.q(query);
 		}
 
-		if (/^@[a-zA-Z0-9-]+$/.test(query)) {
+		if (/^@[a-zA-Z0-9_]+$/.test(query)) {
 			return await this.showUserCommand(query);
 		}
 
diff --git a/src/index.ts b/src/index.ts
index 218455d6f..a8181acda 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -89,7 +89,6 @@ function workerMain() {
  */
 async function init(): Promise<Config> {
 	Logger.info('Welcome to Misskey!');
-	Logger.info(chalk.bold('Misskey <aoi>'));
 	Logger.info('Initializing...');
 
 	EnvironmentInfo.show();
diff --git a/src/web/app/common/views/components/signin.vue b/src/web/app/common/views/components/signin.vue
index 243468408..273143262 100644
--- a/src/web/app/common/views/components/signin.vue
+++ b/src/web/app/common/views/components/signin.vue
@@ -1,7 +1,7 @@
 <template>
 <form class="mk-signin" :class="{ signing }" @submit.prevent="onSubmit">
 	<label class="user-name">
-		<input v-model="username" type="text" pattern="^[a-zA-Z0-9-]+$" placeholder="%i18n:common.tags.mk-signin.username%" autofocus required @change="onUsernameChange"/>%fa:at%
+		<input v-model="username" type="text" pattern="^[a-zA-Z0-9_]+$" placeholder="%i18n:common.tags.mk-signin.username%" autofocus required @change="onUsernameChange"/>%fa:at%
 	</label>
 	<label class="password">
 		<input v-model="password" type="password" placeholder="%i18n:common.tags.mk-signin.password%" required/>%fa:lock%
diff --git a/src/web/app/common/views/components/signup.vue b/src/web/app/common/views/components/signup.vue
index c2e78aa8a..e77d849ad 100644
--- a/src/web/app/common/views/components/signup.vue
+++ b/src/web/app/common/views/components/signup.vue
@@ -2,7 +2,7 @@
 <form class="mk-signup" @submit.prevent="onSubmit" autocomplete="off">
 	<label class="username">
 		<p class="caption">%fa:at%%i18n:common.tags.mk-signup.username%</p>
-		<input v-model="username" type="text" pattern="^[a-zA-Z0-9-]{3,20}$" placeholder="a~z、A~Z、0~9、-" autocomplete="off" required @input="onChangeUsername"/>
+		<input v-model="username" type="text" pattern="^[a-zA-Z0-9_]{3,20}$" placeholder="a~z、A~Z、0~9、-" autocomplete="off" required @input="onChangeUsername"/>
 		<p class="profile-page-url-preview" v-if="shouldShowProfileUrl">{{ `${url}/@${username}` }}</p>
 		<p class="info" v-if="usernameState == 'wait'" style="color:#999">%fa:spinner .pulse .fw%%i18n:common.tags.mk-signup.checking%</p>
 		<p class="info" v-if="usernameState == 'ok'" style="color:#3CB7B5">%fa:check .fw%%i18n:common.tags.mk-signup.available%</p>
diff --git a/src/web/app/common/views/directives/autocomplete.ts b/src/web/app/common/views/directives/autocomplete.ts
index 3440c4212..94635d301 100644
--- a/src/web/app/common/views/directives/autocomplete.ts
+++ b/src/web/app/common/views/directives/autocomplete.ts
@@ -77,7 +77,7 @@ class Autocomplete {
 
 		if (mentionIndex != -1 && mentionIndex > emojiIndex) {
 			const username = text.substr(mentionIndex + 1);
-			if (username != '' && username.match(/^[a-zA-Z0-9-]+$/)) {
+			if (username != '' && username.match(/^[a-zA-Z0-9_]+$/)) {
 				this.open('user', username);
 				opened = true;
 			}
diff --git a/src/web/app/common/views/widgets/version.vue b/src/web/app/common/views/widgets/version.vue
index 5072d9b74..30b632b39 100644
--- a/src/web/app/common/views/widgets/version.vue
+++ b/src/web/app/common/views/widgets/version.vue
@@ -1,16 +1,17 @@
 <template>
-<p>ver {{ v }} (葵 aoi)</p>
+<p>ver {{ version }} ({{ codename }})</p>
 </template>
 
 <script lang="ts">
-import { version } from '../../../config';
+import { version, codename } from '../../../config';
 import define from '../../../common/define-widget';
 export default define({
 	name: 'version'
 }).extend({
 	data() {
 		return {
-			v: version
+			version,
+			codename
 		};
 	}
 });
diff --git a/src/web/app/config.ts b/src/web/app/config.ts
index 8ea6f7010..522d7ff05 100644
--- a/src/web/app/config.ts
+++ b/src/web/app/config.ts
@@ -7,13 +7,13 @@ declare const _DOCS_URL_: string;
 declare const _STATS_URL_: string;
 declare const _STATUS_URL_: string;
 declare const _DEV_URL_: string;
-declare const _CH_URL_: string;
 declare const _LANG_: string;
 declare const _RECAPTCHA_SITEKEY_: string;
 declare const _SW_PUBLICKEY_: string;
 declare const _THEME_COLOR_: string;
 declare const _COPYRIGHT_: string;
 declare const _VERSION_: string;
+declare const _CODENAME_: string;
 declare const _LICENSE_: string;
 declare const _GOOGLE_MAPS_API_KEY_: string;
 
@@ -26,12 +26,12 @@ export const docsUrl = _DOCS_URL_;
 export const statsUrl = _STATS_URL_;
 export const statusUrl = _STATUS_URL_;
 export const devUrl = _DEV_URL_;
-export const chUrl = _CH_URL_;
 export const lang = _LANG_;
 export const recaptchaSitekey = _RECAPTCHA_SITEKEY_;
 export const swPublickey = _SW_PUBLICKEY_;
 export const themeColor = _THEME_COLOR_;
 export const copyright = _COPYRIGHT_;
 export const version = _VERSION_;
+export const codename = _CODENAME_;
 export const license = _LICENSE_;
 export const googleMapsApiKey = _GOOGLE_MAPS_API_KEY_;
diff --git a/src/web/app/dev/views/new-app.vue b/src/web/app/dev/views/new-app.vue
index 344e8468f..1a796299c 100644
--- a/src/web/app/dev/views/new-app.vue
+++ b/src/web/app/dev/views/new-app.vue
@@ -6,12 +6,12 @@
 				<b-form-input v-model="name" type="text" placeholder="ex) Misskey for iOS" autocomplete="off" required/>
 			</b-form-group>
 			<b-form-group label="ID" description="あなたのアプリのID。">
-				<b-input v-model="nid" type="text" pattern="^[a-zA-Z0-9-]{3,30}$" placeholder="ex) misskey-for-ios" autocomplete="off" required/>
+				<b-input v-model="nid" type="text" pattern="^[a-zA-Z0-9_]{3,30}$" placeholder="ex) misskey-for-ios" autocomplete="off" required/>
 				<p class="info" v-if="nidState == 'wait'" style="color:#999">%fa:spinner .pulse .fw%確認しています...</p>
 				<p class="info" v-if="nidState == 'ok'" style="color:#3CB7B5">%fa:fw check%利用できます</p>
 				<p class="info" v-if="nidState == 'unavailable'" style="color:#FF1161">%fa:fw exclamation-triangle%既に利用されています</p>
 				<p class="info" v-if="nidState == 'error'" style="color:#FF1161">%fa:fw exclamation-triangle%通信エラー</p>
-				<p class="info" v-if="nidState == 'invalid-format'" style="color:#FF1161">%fa:fw exclamation-triangle%a~z、A~Z、0~9、-(ハイフン)が使えます</p>
+				<p class="info" v-if="nidState == 'invalid-format'" style="color:#FF1161">%fa:fw exclamation-triangle%a~z、A~Z、0~9、_が使えます</p>
 				<p class="info" v-if="nidState == 'min-range'" style="color:#FF1161">%fa:fw exclamation-triangle%3文字以上でお願いします！</p>
 				<p class="info" v-if="nidState == 'max-range'" style="color:#FF1161">%fa:fw exclamation-triangle%30文字以内でお願いします</p>
 			</b-form-group>
diff --git a/src/web/app/init.ts b/src/web/app/init.ts
index 521dade86..3e5c38961 100644
--- a/src/web/app/init.ts
+++ b/src/web/app/init.ts
@@ -14,7 +14,7 @@ import ElementLocaleJa from 'element-ui/lib/locale/lang/ja';
 import App from './app.vue';
 import checkForUpdate from './common/scripts/check-for-update';
 import MiOS, { API } from './common/mios';
-import { version, hostname, lang } from './config';
+import { version, codename, hostname, lang } from './config';
 
 let elementLocale;
 switch (lang) {
@@ -51,7 +51,7 @@ Vue.mixin({
  * APP ENTRY POINT!
  */
 
-console.info(`Misskey v${version} (葵 aoi)`);
+console.info(`Misskey v${version} (${codename})`);
 console.info(
 	'%cここにコードを入力したり張り付けたりしないでください。アカウントが不正利用される可能性があります。',
 	'color: red; background: yellow; font-size: 16px; font-weight: bold;');
diff --git a/src/web/app/mobile/views/pages/settings.vue b/src/web/app/mobile/views/pages/settings.vue
index 3250999e1..a945a21c5 100644
--- a/src/web/app/mobile/views/pages/settings.vue
+++ b/src/web/app/mobile/views/pages/settings.vue
@@ -12,19 +12,20 @@
 		<ul>
 			<li><a @click="signout">%fa:power-off%%i18n:mobile.tags.mk-settings-page.signout%</a></li>
 		</ul>
-		<p><small>ver {{ v }} (葵 aoi)</small></p>
+		<p><small>ver {{ version }} ({{ codename }})</small></p>
 	</div>
 </mk-ui>
 </template>
 
 <script lang="ts">
 import Vue from 'vue';
-import { version } from '../../../config';
+import { version, codename } from '../../../config';
 
 export default Vue.extend({
 	data() {
 		return {
-			v: version
+			version,
+			codename
 		};
 	},
 	mounted() {
diff --git a/src/web/app/mobile/views/pages/welcome.vue b/src/web/app/mobile/views/pages/welcome.vue
index 3384ee699..855744834 100644
--- a/src/web/app/mobile/views/pages/welcome.vue
+++ b/src/web/app/mobile/views/pages/welcome.vue
@@ -6,7 +6,7 @@
 		<p>%fa:lock% ログイン</p>
 		<div>
 			<form @submit.prevent="onSubmit">
-				<input v-model="username" type="text" pattern="^[a-zA-Z0-9-]+$" placeholder="ユーザー名" autofocus required @change="onUsernameChange"/>
+				<input v-model="username" type="text" pattern="^[a-zA-Z0-9_]+$" placeholder="ユーザー名" autofocus required @change="onUsernameChange"/>
 				<input v-model="password" type="password" placeholder="パスワード" required/>
 				<input v-if="user && user.account.two_factor_enabled" v-model="token" type="number" placeholder="トークン" required/>
 				<button type="submit" :disabled="signing">{{ signing ? 'ログインしています' : 'ログイン' }}</button>
diff --git a/swagger.js b/swagger.js
index 0cfd2fff0..f6c2ca7fd 100644
--- a/swagger.js
+++ b/swagger.js
@@ -23,7 +23,7 @@ const defaultSwagger = {
   "swagger": "2.0",
   "info": {
     "title": "Misskey API",
-    "version": "aoi"
+    "version": "nighthike"
   },
   "host": "api.misskey.xyz",
   "schemes": [
@@ -218,8 +218,8 @@ options.apis = files.map(c => {return `${apiRoot}/${c}`;});
 if(fs.existsSync('.config/config.yml')){
   var config = yaml.safeLoad(fs.readFileSync('./.config/config.yml', 'utf8'));
   options.swaggerDefinition.host = `api.${config.url.match(/\:\/\/(.+)$/)[1]}`;
-  options.swaggerDefinition.schemes = config.https.enable ? 
-                                      ['https'] : 
+  options.swaggerDefinition.schemes = config.https.enable ?
+                                      ['https'] :
                                       ['http'];
 }
 
diff --git a/tools/migration/node.2018-03-28.appname.js b/tools/migration/node.2018-03-28.appname.js
new file mode 100644
index 000000000..9f16e4720
--- /dev/null
+++ b/tools/migration/node.2018-03-28.appname.js
@@ -0,0 +1,40 @@
+// for Node.js interpret
+
+const { default: App } = require('../../built/api/models/app');
+const { generate } = require('../../built/crypto_key');
+const { default: zip } = require('@prezzemolo/zip')
+
+const migrate = async (app) => {
+	const result = await User.update(app._id, {
+		$set: {
+			'name_id': app.name_id.replace(/\-/g, '_'),
+			'name_id_lower': app.name_id_lower.replace(/\-/g, '_')
+		}
+	});
+	return result.ok === 1;
+}
+
+async function main() {
+	const count = await App.count({});
+
+	const dop = Number.parseInt(process.argv[2]) || 5
+	const idop = ((count - (count % dop)) / dop) + 1
+
+	return zip(
+		1,
+		async (time) => {
+			console.log(`${time} / ${idop}`)
+			const doc = await App.find({}, {
+				limit: dop, skip: time * dop
+			})
+			return Promise.all(doc.map(migrate))
+		},
+		idop
+	).then(a => {
+		const rv = []
+		a.forEach(e => rv.push(...e))
+		return rv
+	})
+}
+
+main().then(console.dir).catch(console.error)
diff --git a/tools/migration/node.2018-03-28.username.js b/tools/migration/node.2018-03-28.username.js
new file mode 100644
index 000000000..222215210
--- /dev/null
+++ b/tools/migration/node.2018-03-28.username.js
@@ -0,0 +1,40 @@
+// for Node.js interpret
+
+const { default: User } = require('../../built/api/models/user');
+const { generate } = require('../../built/crypto_key');
+const { default: zip } = require('@prezzemolo/zip')
+
+const migrate = async (user) => {
+	const result = await User.update(user._id, {
+		$set: {
+			'username': user.username.replace(/\-/g, '_'),
+			'username_lower': user.username_lower.replace(/\-/g, '_')
+		}
+	});
+	return result.ok === 1;
+}
+
+async function main() {
+	const count = await User.count({});
+
+	const dop = Number.parseInt(process.argv[2]) || 5
+	const idop = ((count - (count % dop)) / dop) + 1
+
+	return zip(
+		1,
+		async (time) => {
+			console.log(`${time} / ${idop}`)
+			const doc = await User.find({}, {
+				limit: dop, skip: time * dop
+			})
+			return Promise.all(doc.map(migrate))
+		},
+		idop
+	).then(a => {
+		const rv = []
+		a.forEach(e => rv.push(...e))
+		return rv
+	})
+}
+
+main().then(console.dir).catch(console.error)
diff --git a/webpack.config.ts b/webpack.config.ts
index 9a952c8ef..88af49eb5 100644
--- a/webpack.config.ts
+++ b/webpack.config.ts
@@ -20,6 +20,7 @@ import { licenseHtml } from './src/common/build/license';
 import locales from './locales';
 const meta = require('./package.json');
 const version = meta.version;
+const codename = meta.codename;
 
 //#region Replacer definitions
 global['faReplacement'] = faReplacement;
@@ -76,13 +77,13 @@ module.exports = entries.map(x => {
 		_THEME_COLOR_: constants.themeColor,
 		_COPYRIGHT_: constants.copyright,
 		_VERSION_: version,
+		_CODENAME_: codename,
 		_STATUS_URL_: config.status_url,
 		_STATS_URL_: config.stats_url,
 		_DOCS_URL_: config.docs_url,
 		_API_URL_: config.api_url,
 		_WS_URL_: config.ws_url,
 		_DEV_URL_: config.dev_url,
-		_CH_URL_: config.ch_url,
 		_LANG_: lang,
 		_HOST_: config.host,
 		_HOSTNAME_: config.hostname,