diff --git a/mirai-core-api/src/commonMain/kotlin/event/events/friend.kt b/mirai-core-api/src/commonMain/kotlin/event/events/friend.kt
index bc309ce55..5a38dd007 100644
--- a/mirai-core-api/src/commonMain/kotlin/event/events/friend.kt
+++ b/mirai-core-api/src/commonMain/kotlin/event/events/friend.kt
@@ -32,7 +32,7 @@ public data class FriendRemarkChangeEvent internal constructor(
     public override val friend: Friend,
     public val oldRemark: String,
     public val newRemark: String
-) : FriendEvent, Packet, AbstractEvent()
+) : FriendEvent, Packet, AbstractEvent(), FriendInfoChangeEvent
 
 /**
  * 成功添加了一个新好友的事件
@@ -42,14 +42,14 @@ public data class FriendAddEvent @MiraiInternalApi constructor(
      * 新好友. 已经添加到 [Bot.friends]
      */
     public override val friend: Friend
-) : FriendEvent, Packet, AbstractEvent()
+) : FriendEvent, Packet, AbstractEvent(), FriendInfoChangeEvent
 
 /**
  * 好友已被删除或主动删除的事件.
  */
 public data class FriendDeleteEvent internal constructor(
     public override val friend: Friend
-) : FriendEvent, Packet, AbstractEvent()
+) : FriendEvent, Packet, AbstractEvent(), FriendInfoChangeEvent
 
 /**
  * 一个账号请求添加机器人为好友的事件
@@ -77,7 +77,7 @@ public data class NewFriendRequestEvent internal constructor(
      * 群名片或好友昵称
      */
     public val fromNick: String
-) : BotEvent, Packet, AbstractEvent() {
+) : BotEvent, Packet, AbstractEvent(), FriendInfoChangeEvent {
     @JvmField
     internal val responded: AtomicBoolean = AtomicBoolean(false)
 
@@ -109,7 +109,7 @@ public data class FriendNickChangedEvent internal constructor(
     public override val friend: Friend,
     public val from: String,
     public val to: String
-) : FriendEvent, Packet, AbstractEvent()
+) : FriendEvent, Packet, AbstractEvent(), FriendInfoChangeEvent
 
 /**
  * 好友输入状态改变的事件，当开始输入文字、退出聊天窗口或清空输入框时会触发此事件
diff --git a/mirai-core-api/src/commonMain/kotlin/event/events/types.kt b/mirai-core-api/src/commonMain/kotlin/event/events/types.kt
index 69b846251..9e90afb58 100644
--- a/mirai-core-api/src/commonMain/kotlin/event/events/types.kt
+++ b/mirai-core-api/src/commonMain/kotlin/event/events/types.kt
@@ -90,6 +90,8 @@ public interface FriendEvent : BotEvent, UserEvent {
     override val user: Friend get() = friend
 }
 
+internal interface FriendInfoChangeEvent : BotEvent // for cache
+
 /**
  * 有关陌生人的事件
  */
diff --git a/mirai-core-api/src/commonMain/kotlin/utils/BotConfiguration.kt b/mirai-core-api/src/commonMain/kotlin/utils/BotConfiguration.kt
index ac011c3b7..806fb727b 100644
--- a/mirai-core-api/src/commonMain/kotlin/utils/BotConfiguration.kt
+++ b/mirai-core-api/src/commonMain/kotlin/utils/BotConfiguration.kt
@@ -310,6 +310,43 @@ public open class BotConfiguration { // open for Java
         botLoggerSupplier = { _ -> SilentLogger }
     }
 
+    ///////////////////////////////////////////////////////////////////////////
+    // Cache
+    //////////////////////////////////////////////////////////////////////////
+
+    /**
+     * 非 `null` 时启用好友列表缓存, 加快初始化速度. 在启用后将会在下载好友列表后保存到文件, 并在修改时自动保存.
+     * @since 2.4
+     * @see enableFriendListCache
+     */
+    public var friendListCache: FriendListCache? = FriendListCache()
+
+    /**
+     * 好友列表缓存设置.
+     * @since 2.4
+     * @see friendListCache
+     */
+    public class FriendListCache @JvmOverloads constructor(
+        /**
+         * 缓存文件位置, 相对于 [workingDir] 的路径.
+         */
+        public val cacheFile: File = File("cache/friendList.json"),
+        /**
+         * 在有好友列表修改是
+         */
+        public val saveIntervalMillis: Long = 60_000,
+    )
+
+    /**
+     * 启用好友列表缓存.
+     * @since 2.4
+     * @see BotConfiguration.enableFriendListCache
+     */
+    public fun enableFriendListCache() {
+        friendListCache = FriendListCache()
+    }
+
+
     /**
      * 使用当前协程的 [coroutineContext] 作为 [parentCoroutineContext].
      *
diff --git a/mirai-core-utils/src/commonMain/kotlin/IO.kt b/mirai-core-utils/src/commonMain/kotlin/IO.kt
index 2969e81d0..0899301b2 100644
--- a/mirai-core-utils/src/commonMain/kotlin/IO.kt
+++ b/mirai-core-utils/src/commonMain/kotlin/IO.kt
@@ -16,6 +16,7 @@ package net.mamoe.mirai.utils
 
 import io.ktor.utils.io.charsets.*
 import kotlinx.io.core.*
+import java.io.File
 import kotlin.text.Charsets
 
 
@@ -123,4 +124,11 @@ public inline fun Input.readString(length: UShort, charset: Charset = Charsets.U
     String(this.readBytes(length.toInt()), charset = charset)
 
 public inline fun Input.readString(length: Byte, charset: Charset = Charsets.UTF_8): String =
-    String(this.readBytes(length.toInt()), charset = charset)
\ No newline at end of file
+    String(this.readBytes(length.toInt()), charset = charset)
+
+public fun File.createFileIfNotExists() {
+    if (!this.exists()) {
+        this.parentFile.mkdirs()
+        this.createNewFile()
+    }
+}
\ No newline at end of file
diff --git a/mirai-core-utils/src/commonMain/kotlin/Serialization.kt b/mirai-core-utils/src/commonMain/kotlin/Serialization.kt
new file mode 100644
index 000000000..fc2c64f20
--- /dev/null
+++ b/mirai-core-utils/src/commonMain/kotlin/Serialization.kt
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.utils
+
+import kotlinx.serialization.DeserializationStrategy
+import kotlinx.serialization.StringFormat
+import java.io.File
+
+public fun <T> File.loadAs(
+    serializer: DeserializationStrategy<T>,
+    stringFormat: StringFormat,
+): T? {
+    if (!this.exists() || this.length() == 0L) {
+        return null
+    }
+    return stringFormat.decodeFromString(serializer, this.readText())
+}
diff --git a/mirai-core/src/commonMain/kotlin/QQAndroidBot.kt b/mirai-core/src/commonMain/kotlin/QQAndroidBot.kt
index 8dc5277fa..57d5eef1d 100644
--- a/mirai-core/src/commonMain/kotlin/QQAndroidBot.kt
+++ b/mirai-core/src/commonMain/kotlin/QQAndroidBot.kt
@@ -18,26 +18,25 @@ import net.mamoe.mirai.LowLevelApi
 import net.mamoe.mirai.Mirai
 import net.mamoe.mirai.contact.*
 import net.mamoe.mirai.data.*
-import net.mamoe.mirai.internal.contact.info.FriendInfoImpl
 import net.mamoe.mirai.internal.contact.OtherClientImpl
-import net.mamoe.mirai.internal.contact.info.StrangerInfoImpl
 import net.mamoe.mirai.internal.contact.checkIsGroupImpl
+import net.mamoe.mirai.internal.contact.info.FriendInfoImpl
+import net.mamoe.mirai.internal.contact.info.StrangerInfoImpl
 import net.mamoe.mirai.internal.contact.uin
 import net.mamoe.mirai.internal.message.*
-import net.mamoe.mirai.internal.network.Packet
-import net.mamoe.mirai.internal.network.QQAndroidClient
+import net.mamoe.mirai.internal.network.*
 import net.mamoe.mirai.internal.network.handler.QQAndroidBotNetworkHandler
 import net.mamoe.mirai.internal.network.protocol.packet.OutgoingPacket
 import net.mamoe.mirai.internal.network.protocol.packet.OutgoingPacketWithRespType
 import net.mamoe.mirai.internal.network.protocol.packet.chat.*
 import net.mamoe.mirai.internal.network.protocol.packet.login.StatSvc
-import net.mamoe.mirai.internal.network.useNextServers
+import net.mamoe.mirai.internal.utils.ScheduledJob
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.network.LoginFailedException
 import net.mamoe.mirai.utils.*
 import kotlin.contracts.contract
 import kotlin.coroutines.CoroutineContext
-import net.mamoe.mirai.internal.network.protocol.data.jce.FriendInfo as JceFriendInfo
+import kotlin.time.milliseconds
 
 internal fun Bot.asQQAndroidBot(): QQAndroidBot {
     contract {
@@ -59,7 +58,7 @@ internal class QQAndroidBot constructor(
     configuration: BotConfiguration
 ) : AbstractBot<QQAndroidBotNetworkHandler>(configuration, account.id) {
     var client: QQAndroidClient = initClient()
-    private set
+        private set
 
     fun initClient(): QQAndroidClient {
         client = QQAndroidClient(
@@ -78,6 +77,40 @@ internal class QQAndroidBot constructor(
 
     override val friends: ContactList<Friend> = ContactList()
 
+    val friendListCache: FriendListCache? by lazy {
+        configuration.friendListCache?.cacheFile?.run {
+            val ret = loadAs(FriendListCache.serializer(), JsonForCache) ?: FriendListCache()
+
+            @Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
+            bot.eventChannel.parentScope(this@QQAndroidBot)
+                .subscribeAlways<net.mamoe.mirai.event.events.FriendInfoChangeEvent> {
+                    friendListSaver?.notice()
+                }
+
+            ret
+        }
+    }
+
+    private val friendListSaver by lazy {
+        configuration.friendListCache?.let { friendListCache: BotConfiguration.FriendListCache ->
+
+            ScheduledJob(coroutineContext, friendListCache.saveIntervalMillis.milliseconds) {
+                runBIO { saveFriendCache() }
+            }
+        }
+    }
+
+    fun saveFriendCache() {
+        val friendListCache = friendListCache
+        if (friendListCache != null) {
+            configuration.friendListCache?.cacheFile?.run {
+                createFileIfNotExists()
+                writeText(JsonForCache.encodeToString(FriendListCache.serializer(), friendListCache))
+                bot.network.logger.info { "Saved ${friendListCache.list.size} friends to local cache." }
+            }
+        }
+    }
+
     override lateinit var nick: String
 
     override val asFriend: Friend by lazy {
@@ -100,7 +133,7 @@ internal class QQAndroidBot constructor(
 
     override suspend fun sendLogout() {
         network.run {
-            StatSvc.Register.offline(client).    sendWithoutExpect()
+            StatSvc.Register.offline(client).sendWithoutExpect()
         }
     }
 
diff --git a/mirai-core/src/commonMain/kotlin/network/ContactUpdater.kt b/mirai-core/src/commonMain/kotlin/network/ContactUpdater.kt
index 43e5a0144..2d50bdf06 100644
--- a/mirai-core/src/commonMain/kotlin/network/ContactUpdater.kt
+++ b/mirai-core/src/commonMain/kotlin/network/ContactUpdater.kt
@@ -17,13 +17,17 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Semaphore
 import kotlinx.coroutines.sync.withPermit
 import net.mamoe.mirai.Mirai
+import net.mamoe.mirai.data.FriendInfo
 import net.mamoe.mirai.internal.QQAndroidBot
 import net.mamoe.mirai.internal.contact.FriendImpl
 import net.mamoe.mirai.internal.contact.GroupImpl
+import net.mamoe.mirai.internal.contact.info.FriendInfoImpl
 import net.mamoe.mirai.internal.contact.info.GroupInfoImpl
 import net.mamoe.mirai.internal.contact.info.StrangerInfoImpl
 import net.mamoe.mirai.internal.contact.toMiraiFriendInfo
 import net.mamoe.mirai.internal.network.protocol.data.jce.StTroopNum
+import net.mamoe.mirai.internal.network.protocol.data.jce.SvcRespRegister
+import net.mamoe.mirai.internal.network.protocol.data.jce.isValid
 import net.mamoe.mirai.internal.network.protocol.packet.chat.TroopManagement
 import net.mamoe.mirai.internal.network.protocol.packet.list.FriendList
 import net.mamoe.mirai.internal.network.protocol.packet.list.StrangerList
@@ -31,11 +35,8 @@ import net.mamoe.mirai.utils.info
 import net.mamoe.mirai.utils.retryCatching
 import net.mamoe.mirai.utils.verbose
 
-internal interface ContactCache {
-}
-
 internal interface ContactUpdater {
-    suspend fun loadAll()
+    suspend fun loadAll(registerResp: SvcRespRegister)
 
     fun closeAllContacts(e: CancellationException)
 }
@@ -44,9 +45,9 @@ internal class ContactUpdaterImpl(
     val bot: QQAndroidBot,
 ) : ContactUpdater {
     @Synchronized
-    override suspend fun loadAll() {
+    override suspend fun loadAll(registerResp: SvcRespRegister) {
         coroutineScope {
-            launch { reloadFriendList() }
+            launch { reloadFriendList(registerResp) }
             launch { reloadGroupList() }
             launch { reloadStrangerList() }
         }
@@ -78,48 +79,80 @@ internal class ContactUpdaterImpl(
     /**
      * Don't use concurrently
      */
-    private suspend fun reloadFriendList() = bot.network.run {
+    private suspend fun reloadFriendList(registerResp: SvcRespRegister) = bot.network.run {
         if (initFriendOk) {
             return
         }
 
-        logger.info { "Start loading friend list..." }
-        var currentFriendCount = 0
-        var totalFriendCount: Short
-        while (true) {
-            val data = FriendList.GetFriendGroupList(
-                bot.client, currentFriendCount, 150, 0, 0
-            ).sendAndExpect<FriendList.GetFriendGroupList.Response>(timeoutMillis = 5000, retry = 2)
+        val friendListCache = bot.friendListCache
 
-            totalFriendCount = data.totalFriendCount
-            data.friendList.forEach {
-                // atomic
-                bot.friends.delegate.add(
-                    FriendImpl(bot, bot.coroutineContext, it.toMiraiFriendInfo())
-                ).also { currentFriendCount++ }
+        fun updateCacheSeq(list: List<FriendInfoImpl>) {
+            bot.friendListCache?.apply {
+                friendListSeq = registerResp.iLargeSeq
+                timeStamp = registerResp.timeStamp
+                this.list = list
+                bot.saveFriendCache()
             }
-            logger.verbose { "Loading friend list: ${currentFriendCount}/${totalFriendCount}" }
-            if (currentFriendCount >= totalFriendCount) {
-                break
-            }
-            // delay(200)
         }
-        logger.info { "Successfully loaded friend list: $currentFriendCount in total" }
+
+        suspend fun refreshFriendList(): List<FriendInfoImpl> {
+            logger.info { "Start loading friend list..." }
+            val friendInfos = mutableListOf<FriendInfoImpl>()
+
+            var count = 0
+            var total: Short
+            while (true) {
+                val data = FriendList.GetFriendGroupList(
+                    bot.client, count, 150, 0, 0
+                ).sendAndExpect<FriendList.GetFriendGroupList.Response>(timeoutMillis = 5000, retry = 2)
+
+                total = data.totalFriendCount
+
+                for (jceInfo in data.friendList) {
+                    friendInfos.add(jceInfo.toMiraiFriendInfo())
+                }
+
+                count += data.friendList.size
+                logger.verbose { "Loading friend list: ${count}/${total}" }
+                if (count >= total) break
+            }
+            logger.info { "Successfully loaded friend list: $count in total" }
+            return friendInfos
+        }
+
+        val list = if (friendListCache?.isValid(registerResp) == true) {
+            val list = friendListCache.list
+            bot.network.logger.info { "Loaded ${list.size} friends from local cache." }
+            list
+        } else {
+            refreshFriendList().also {
+                updateCacheSeq(it)
+            }
+        }
+
+        for (friendInfoImpl in list) {
+            addFriendToBot(friendInfoImpl)
+        }
+
+
         initFriendOk = true
     }
 
-    private suspend fun StTroopNum.reloadGroup() {
+    private fun addFriendToBot(it: FriendInfo) =
+        bot.friends.delegate.add(FriendImpl(bot, bot.coroutineContext, it))
+
+    private suspend fun addGroupToBot(stTroopNum: StTroopNum) {
         bot.groups.delegate.add(
             GroupImpl(
                 bot = bot,
                 coroutineContext = bot.coroutineContext,
-                id = groupCode,
-                groupInfo = GroupInfoImpl(this),
+                id = stTroopNum.groupCode,
+                groupInfo = GroupInfoImpl(stTroopNum),
                 members = Mirai.getRawGroupMemberList(
                     bot,
-                    groupUin,
-                    groupCode,
-                    dwGroupOwnerUin
+                    stTroopNum.groupUin,
+                    stTroopNum.groupCode,
+                    stTroopNum.dwGroupOwnerUin
                 )
             )
         )
@@ -165,7 +198,7 @@ internal class ContactUpdaterImpl(
             troopListData.groups.forEach { group ->
                 launch {
                     semaphore.withPermit {
-                        retryCatching(5) { group.reloadGroup() }.getOrThrow()
+                        retryCatching(5) { addGroupToBot(group) }.getOrThrow()
                     }
                 }
             }
diff --git a/mirai-core/src/commonMain/kotlin/network/FriendListCache.kt b/mirai-core/src/commonMain/kotlin/network/FriendListCache.kt
new file mode 100644
index 000000000..b4786c15d
--- /dev/null
+++ b/mirai-core/src/commonMain/kotlin/network/FriendListCache.kt
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
+ *
+ *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ *  https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.internal.network
+
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import net.mamoe.mirai.internal.contact.info.FriendInfoImpl
+
+internal val JsonForCache = Json {
+    encodeDefaults = true
+    ignoreUnknownKeys = true
+    isLenient = true
+}
+
+@Serializable
+internal data class FriendListCache(
+    var friendListSeq: Long = 0,
+    /**
+     * 实际上是个序列号, 不是时间
+     */
+    var timeStamp: Long = 0,
+    var list: List<FriendInfoImpl> = emptyList(),
+)
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/network/handler/QQAndroidBotNetworkHandler.kt b/mirai-core/src/commonMain/kotlin/network/handler/QQAndroidBotNetworkHandler.kt
index aed759b6d..fee835efa 100644
--- a/mirai-core/src/commonMain/kotlin/network/handler/QQAndroidBotNetworkHandler.kt
+++ b/mirai-core/src/commonMain/kotlin/network/handler/QQAndroidBotNetworkHandler.kt
@@ -265,13 +265,8 @@ internal class QQAndroidBotNetworkHandler(coroutineContext: CoroutineContext, bo
 
         // println("d2key=${bot.client.wLoginSigInfo.d2Key.toUHexString()}")
         registerClientOnline()
-
         startHeartbeatJobOrKill()
 
-        bot.otherClientsLock.withLock {
-            updateOtherClientsList()
-        }
-
         launch {
             while (isActive) {
                 bot.client.wLoginSigInfo.sKey.run {
@@ -292,17 +287,17 @@ internal class QQAndroidBotNetworkHandler(coroutineContext: CoroutineContext, bo
         WtLogin15(bot.client).sendAndExpect()
     }
 
-    private suspend fun registerClientOnline() {
+    private suspend fun registerClientOnline(): StatSvc.Register.Response {
 //        object : OutgoingPacketFactory<Packet?>("push.proxyUnRegister") {
 //            override suspend fun ByteReadPacket.decode(bot: QQAndroidBot): Packet? {
 //                return null
 //            }
 //        }.buildOutgoingUniPacket(bot.client) {}.sendWithoutExpect()
-        kotlin.runCatching {
-            StatSvc.Register.offline(bot.client).sendAndExpect()
-        }.getOrElse { logger.warning(it) }
+     //  kotlin.runCatching {
+     //      StatSvc.Register.offline(bot.client).sendAndExpect()
+     //  }.getOrElse { logger.warning(it) }
 
-        StatSvc.Register.online(bot.client).sendAndExpect()
+        return StatSvc.Register.online(bot.client).sendAndExpect()
     }
 
     private suspend fun updateOtherClientsList() {
@@ -332,23 +327,34 @@ internal class QQAndroidBotNetworkHandler(coroutineContext: CoroutineContext, bo
         check(bot.isActive) { "bot is dead therefore network can't init." }
         check(this@QQAndroidBotNetworkHandler.isActive) { "network is dead therefore can't init." }
 
-            contactUpdater.closeAllContacts(CancellationException("re-init"))
+        contactUpdater.closeAllContacts(CancellationException("re-init"))
 
         if (!pendingEnabled) {
             pendingIncomingPackets = ConcurrentLinkedQueue()
             _pendingEnabled.value = true
         }
 
-            contactUpdater.loadAll()
+        val registerResp = registerClientOnline()
 
         this@QQAndroidBotNetworkHandler.launch(CoroutineName("Awaiting ConfigPushSvc.PushReq"), block= ConfigPushSyncer())
 
-        syncMessageSvc()
+        launch {
+            syncMessageSvc()
+        }
+
+        launch {
+            bot.otherClientsLock.withLock {
+                updateOtherClientsList()
+            }
+        }
+
+        contactUpdater.loadAll(registerResp.origin)
 
         bot.firstLoginSucceed = true
         postInitActions()
     }
 
+    @Suppress("FunctionName")
     private fun BotNetworkHandler.ConfigPushSyncer(): suspend CoroutineScope.() -> Unit = launch@{
         logger.info { "Awaiting ConfigPushSvc.PushReq." }
         when (val resp: ConfigPushSvc.PushReq.PushReqResponse? = nextEventOrNull(20_000)) {
diff --git a/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcReqRegister.kt b/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcReqRegister.kt
index dd1c5aae6..9d1ff5990 100644
--- a/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcReqRegister.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcReqRegister.kt
@@ -15,41 +15,41 @@ import net.mamoe.mirai.internal.utils.io.serialization.tars.TarsId
 
 @Serializable
 internal class SvcReqRegister(
-    @TarsId(0) @JvmField val lUin: Long = 0L,
-    @TarsId(1) @JvmField val lBid: Long = 0L,
-    @TarsId(2) @JvmField val cConnType: Byte = 0,
-    @TarsId(3) @JvmField val sOther: String = "",
-    @TarsId(4) @JvmField val iStatus: Int = 11,
-    @TarsId(5) @JvmField val bOnlinePush: Byte = 0,
-    @TarsId(6) @JvmField val bIsOnline: Byte = 0,
-    @TarsId(7) @JvmField val bIsShowOnline: Byte = 0,
-    @TarsId(8) @JvmField val bKikPC: Byte = 0,
-    @TarsId(9) @JvmField val bKikWeak: Byte = 0,
-    @TarsId(10) @JvmField val timeStamp: Long = 0L,
-    @TarsId(11) @JvmField val iOSVersion: Long = 0L,
-    @TarsId(12) @JvmField val cNetType: Byte = 0,
-    @TarsId(13) @JvmField val sBuildVer: String? = "",
-    @TarsId(14) @JvmField val bRegType: Byte = 0,
-    @TarsId(15) @JvmField val vecDevParam: ByteArray? = null,
-    @TarsId(16) @JvmField val vecGuid: ByteArray? = null,
-    @TarsId(17) @JvmField val iLocaleID: Int = 2052,
-    @TarsId(18) @JvmField val bSlientPush: Byte = 0,
-    @TarsId(19) @JvmField val strDevName: String? = null,
-    @TarsId(20) @JvmField val strDevType: String? = null,
-    @TarsId(21) @JvmField val strOSVer: String? = null,
-    @TarsId(22) @JvmField val bOpenPush: Byte,
-    @TarsId(23) @JvmField val iLargeSeq: Long,
-    @TarsId(24) @JvmField val iLastWatchStartTime: Long = 0L,
-    @TarsId(26) @JvmField val uOldSSOIp: Long = 0L,
-    @TarsId(27) @JvmField val uNewSSOIp: Long = 0L,
-    @TarsId(28) @JvmField val sChannelNo: String? = null,
-    @TarsId(29) @JvmField val lCpId: Long = 0L,
-    @TarsId(30) @JvmField val strVendorName: String? = null,
-    @TarsId(31) @JvmField val strVendorOSName: String? = null,
-    @TarsId(32) @JvmField val strIOSIdfa: String? = null,
-    @TarsId(33) @JvmField val bytes_0x769_reqbody: ByteArray? = null,
-    @TarsId(34) @JvmField val bIsSetStatus: Byte = 0,
-    @TarsId(35) @JvmField val vecServerBuf: ByteArray? = null,
-    @TarsId(36) @JvmField val bSetMute: Byte = 0
+    @TarsId(0) @JvmField var lUin: Long = 0L,
+    @TarsId(1) @JvmField var lBid: Long = 0L,
+    @TarsId(2) @JvmField var cConnType: Byte = 0,
+    @TarsId(3) @JvmField var sOther: String = "",
+    @TarsId(4) @JvmField var iStatus: Int = 11,
+    @TarsId(5) @JvmField var bOnlinePush: Byte = 0,
+    @TarsId(6) @JvmField var bIsOnline: Byte = 0,
+    @TarsId(7) @JvmField var bIsShowOnline: Byte = 0,
+    @TarsId(8) @JvmField var bKikPC: Byte = 0,
+    @TarsId(9) @JvmField var bKikWeak: Byte = 0,
+    @TarsId(10) @JvmField var timeStamp: Long = 0L,
+    @TarsId(11) @JvmField var iOSVersion: Long = 0L,
+    @TarsId(12) @JvmField var cNetType: Byte = 0,
+    @TarsId(13) @JvmField var sBuildVer: String? = "",
+    @TarsId(14) @JvmField var bRegType: Byte = 0,
+    @TarsId(15) @JvmField var vecDevParam: ByteArray? = null,
+    @TarsId(16) @JvmField var vecGuid: ByteArray? = null,
+    @TarsId(17) @JvmField var iLocaleID: Int = 2052,
+    @TarsId(18) @JvmField var bSlientPush: Byte = 0,
+    @TarsId(19) @JvmField var strDevName: String? = null,
+    @TarsId(20) @JvmField var strDevType: String? = null,
+    @TarsId(21) @JvmField var strOSVer: String? = null,
+    @TarsId(22) @JvmField var bOpenPush: Byte,
+    @TarsId(23) @JvmField var iLargeSeq: Long,
+    @TarsId(24) @JvmField var iLastWatchStartTime: Long = 0L,
+    @TarsId(26) @JvmField var uOldSSOIp: Long = 0L,
+    @TarsId(27) @JvmField var uNewSSOIp: Long = 0L,
+    @TarsId(28) @JvmField var sChannelNo: String? = null,
+    @TarsId(29) @JvmField var lCpId: Long = 0L,
+    @TarsId(30) @JvmField var strVendorName: String? = null,
+    @TarsId(31) @JvmField var strVendorOSName: String? = null,
+    @TarsId(32) @JvmField var strIOSIdfa: String? = null,
+    @TarsId(33) @JvmField var bytes_0x769_reqbody: ByteArray? = null,
+    @TarsId(34) @JvmField var bIsSetStatus: Byte = 0,
+    @TarsId(35) @JvmField var vecServerBuf: ByteArray? = null,
+    @TarsId(36) @JvmField var bSetMute: Byte = 0
     // @SerialId(25) var vecBindUin: ArrayList<*>? = null // ?? 未知泛型
 ) : JceStruct
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcRespRegister.kt b/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcRespRegister.kt
index 0053f81ed..308d493c7 100644
--- a/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcRespRegister.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/data/jce/SvcRespRegister.kt
@@ -10,6 +10,7 @@
 package net.mamoe.mirai.internal.network.protocol.data.jce
 
 import kotlinx.serialization.Serializable
+import net.mamoe.mirai.internal.network.FriendListCache
 import net.mamoe.mirai.internal.utils.io.JceStruct
 import net.mamoe.mirai.internal.utils.io.serialization.tars.TarsId
 
@@ -30,7 +31,15 @@ internal class SvcRespRegister(
     @JvmField @TarsId(11) val iClientPort: Int = 0,
     @JvmField @TarsId(12) val iHelloInterval: Int = 300,
     @JvmField @TarsId(13) val iLargeSeq: Long = 0L,
+    /**
+     * =1 好友列表更新
+     */
     @JvmField @TarsId(14) val largeSeqUpdate: Byte = 0,
     @JvmField @TarsId(15) val bytes_0x769_rspBody: ByteArray? = null,
     @JvmField @TarsId(16) val iStatus: Int? = 0
 ) : JceStruct
+
+internal fun FriendListCache.isValid(svcRespRegister: SvcRespRegister): Boolean {
+    return svcRespRegister.iLargeSeq == friendListSeq && svcRespRegister.timeStamp == timeStamp
+//    return this.largeSeqUpdate != 0.toByte()
+}
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/network/protocol/packet/login/StatSvc.kt b/mirai-core/src/commonMain/kotlin/network/protocol/packet/login/StatSvc.kt
index da02eb756..c4706eca1 100644
--- a/mirai-core/src/commonMain/kotlin/network/protocol/packet/login/StatSvc.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/packet/login/StatSvc.kt
@@ -25,6 +25,7 @@ import net.mamoe.mirai.internal.QQAndroidBot
 import net.mamoe.mirai.internal.contact.appId
 import net.mamoe.mirai.internal.createOtherClient
 import net.mamoe.mirai.internal.message.contextualBugReportException
+import net.mamoe.mirai.internal.network.FriendListCache
 import net.mamoe.mirai.internal.network.Packet
 import net.mamoe.mirai.internal.network.QQAndroidClient
 import net.mamoe.mirai.internal.network.getRandomByteArray
@@ -94,29 +95,30 @@ internal class StatSvc {
 
     internal object Register : OutgoingPacketFactory<Register.Response>("StatSvc.register") {
 
-        internal object Response : Packet {
+        internal class Response(
+            val origin: SvcRespRegister
+        ) : Packet {
             override fun toString(): String = "Response(StatSvc.register)"
         }
 
         override suspend fun ByteReadPacket.decode(bot: QQAndroidBot): Response {
             val packet = readUniPacket(SvcRespRegister.serializer())
-            if (packet.updateFlag.toInt() == 1) {
-                //TODO 加载好友列表
-            }
-            if (packet.largeSeqUpdate.toInt() == 1) {
-                //TODO 刷新好友列表
-            }
             packet.iHelloInterval.let {
                 bot.configuration.heartbeatPeriodMillis = it.times(1000).toLong()
             }
 
-            return Response
+            return Response(packet)
         }
 
         fun online(
             client: QQAndroidClient,
             regPushReason: RegPushReason = RegPushReason.appRegister
-        ) = impl(client, 1 or 2 or 4, client.onlineStatus, regPushReason)
+        ) = impl(client, 1 or 2 or 4, client.onlineStatus, regPushReason) {
+            client.bot.friendListCache?.let { friendListCache: FriendListCache ->
+                iLargeSeq = friendListCache.friendListSeq
+              //  timeStamp = friendListCache.timeStamp
+            }
+        }
 
         fun offline(
             client: QQAndroidClient,
@@ -127,7 +129,8 @@ internal class StatSvc {
             client: QQAndroidClient,
             bid: Long,
             status: OnlineStatus,
-            regPushReason: RegPushReason = RegPushReason.appRegister
+            regPushReason: RegPushReason = RegPushReason.appRegister,
+            applyAction: SvcReqRegister.() -> Unit = {}
         ) = buildLoginOutgoingPacket(
             client,
             bodyType = 1,
@@ -198,7 +201,7 @@ internal class StatSvc {
                                     )
                                 ),
                                 bSetMute = 0
-                            )
+                            ).apply(applyAction)
                         )
                     )
                 )
diff --git a/mirai-core/src/commonMain/kotlin/utils/ScheduledJob.kt b/mirai-core/src/commonMain/kotlin/utils/ScheduledJob.kt
new file mode 100644
index 000000000..4a5fa0d5b
--- /dev/null
+++ b/mirai-core/src/commonMain/kotlin/utils/ScheduledJob.kt
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.internal.utils
+
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.receiveAsFlow
+import kotlinx.coroutines.flow.sample
+import kotlin.coroutines.CoroutineContext
+import kotlin.time.Duration
+
+@OptIn(FlowPreview::class)
+internal class ScheduledJob(
+    coroutineContext: CoroutineContext,
+    val interval: Duration,
+    private val task: suspend () -> Unit
+) : CoroutineScope by CoroutineScope(coroutineContext + SupervisorJob(coroutineContext[Job])) {
+    private val coroutineExceptionHandler =
+        coroutineContext[CoroutineExceptionHandler].also {
+            requireNotNull(it) {
+                "Could not init ScheduledJob, coroutineExceptionHandler == null"
+            }
+        }
+
+    private val channel = Channel<Unit>(Channel.CONFLATED)
+
+    fun notice() {
+        if (interval == Duration.ZERO) {
+            launch { task() }
+        } else channel.offer(Unit)
+    }
+
+    private suspend fun doTask() {
+        runCatching {
+            task()
+        }.onFailure {
+            coroutineExceptionHandler!!.handleException(currentCoroutineContext(), it)
+        }
+    }
+
+    init {
+        if (interval != Duration.ZERO) {
+            launch {
+                channel.receiveAsFlow()
+                    .runCatching {
+                        sample(interval.toLongMilliseconds())
+                    }
+                    .fold(
+                        onSuccess = { flow ->
+                            flow.collect { doTask() }
+                        },
+                        onFailure = {
+                            // binary change
+                            while (isActive) {
+                                delay(interval)
+                                task()
+                            }
+                        }
+                    )
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mirai-core/src/commonTest/kotlin/ScheduledJobTest.kt b/mirai-core/src/commonTest/kotlin/ScheduledJobTest.kt
new file mode 100644
index 000000000..d46c84aa3
--- /dev/null
+++ b/mirai-core/src/commonTest/kotlin/ScheduledJobTest.kt
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
+ *
+ *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ *  https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+package net.mamoe.mirai.internal.utils
+
+import kotlinx.coroutines.CoroutineExceptionHandler
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.Test
+import java.util.concurrent.atomic.AtomicInteger
+import kotlin.test.assertEquals
+import kotlin.time.seconds
+
+internal class ScheduledJobTest {
+    @Test
+    fun testScheduledJob() {
+        runBlocking {
+            val scope = CoroutineScope(CoroutineExceptionHandler { _, throwable ->
+                throwable.printStackTrace()
+            })
+            val invoked = AtomicInteger(0)
+            val job = ScheduledJob(scope.coroutineContext, 1.seconds) {
+                invoked.incrementAndGet()
+            }
+            delay(100)
+            assertEquals(0, invoked.get())
+            job.notice()
+            job.notice()
+            job.notice()
+        }
+    }
+}
\ No newline at end of file