diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Identified.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Identified.kt
index 8e1545a3d..93de5cd74 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Identified.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Identified.kt
@@ -10,21 +10,33 @@
 package net.mamoe.mirai.contact
 
 import net.mamoe.mirai.Bot
-import net.mamoe.mirai.utils.MiraiExperimentalAPI
 import net.mamoe.mirai.utils.SinceMirai
 
 /**
  * 拥有 [id] 的对象.
  * 此为 [Contact] 与 [Bot] 的唯一公共接口.
+ * **注意:** 此接口为实验性接口, 将来可能会发生不兼容的更名.
  *
  * @see Contact
  * @see Bot
  */
-@MiraiExperimentalAPI("classname may change")
-@SinceMirai("0.38.0")
+@ExperimentalIdentification("classname may change")
+@SinceMirai("0.37.2")
 interface Identified {
     /**
      * QQ 号或群号.
      */
     val id: Long
-}
\ No newline at end of file
+}
+
+
+/**
+ * 标记使用实验性 [Identified] 接口.
+ */
+@Retention(AnnotationRetention.SOURCE)
+@RequiresOptIn(level = RequiresOptIn.Level.WARNING)
+@Target(AnnotationTarget.CLASS, AnnotationTarget.TYPEALIAS, AnnotationTarget.FUNCTION,
+    AnnotationTarget.PROPERTY, AnnotationTarget.FIELD, AnnotationTarget.CONSTRUCTOR)
+annotation class ExperimentalIdentification(
+    val message: String = ""
+)
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/events/BotEvents.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/events/BotEvents.kt
index e3f68069e..4190ce11c 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/events/BotEvents.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/events/BotEvents.kt
@@ -75,7 +75,7 @@ sealed class BotOfflineEvent : BotEvent {
     /**
      * 服务器主动要求更换另一个服务器
      */
-    @SinceMirai("0.38.0")
+    @SinceMirai("0.37.1")
     data class RequireReconnect(override val bot: Bot) : BotOfflineEvent(), Packet, BotPassiveEvent
 }
 
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/subscribeMessages.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/subscribeMessages.kt
index a63151f0e..ad4cb8d46 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/subscribeMessages.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/subscribeMessages.kt
@@ -458,7 +458,7 @@ open class MessageSubscribersBuilder<M : ContactMessage, out Ret, R : RR, RR>(
 
     /** 如果消息内容 `==` [equals] */
     @MessageDsl
-    @SinceMirai("0.38.0")
+    @SinceMirai("0.37.1")
     operator fun String.invoke(block: MessageListener<M, R>): Ret {
         return case(this, onEvent = block)
     }
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
index 0fbf2ef61..b4e492a40 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
@@ -117,12 +117,14 @@ sealed class OnlineMessageSource : MessageSource() {
      * 消息发送人. 可能为 [机器人][Bot] 或 [好友][QQ] 或 [群员][Member].
      * 即类型必定为 [Bot], [QQ] 或 [Member]
      */
+    @ExperimentalIdentification
     abstract val sender: Identified
 
     /**
      * 消息发送目标. 可能为 [机器人][Bot] 或 [好友][QQ] 或 [群][Group].
      * 即类型必定为 [Bot], [QQ] 或 [Group]
      */
+    @ExperimentalIdentification
     abstract val target: Identified
 
     /**
@@ -134,6 +136,7 @@ sealed class OnlineMessageSource : MessageSource() {
     /**
      * 由 [机器人主动发送消息][Contact.sendMessage] 产生的 [MessageSource]
      */
+    @OptIn(ExperimentalIdentification::class)
     sealed class Outgoing : OnlineMessageSource() {
         companion object Key : Message.Key<Outgoing> {
             override val typeName: String get() = "OnlineMessageSource.Outgoing"
@@ -179,6 +182,7 @@ sealed class OnlineMessageSource : MessageSource() {
     /**
      * 接收到的一条消息的 [MessageSource]
      */
+    @OptIn(ExperimentalIdentification::class)
     sealed class Incoming : OnlineMessageSource() {
         companion object Key : Message.Key<Incoming> {
             override val typeName: String get() = "OnlineMessageSource.Incoming"
@@ -240,6 +244,7 @@ sealed class OnlineMessageSource : MessageSource() {
     @Deprecated("for binary compatibility until 1.0.0", level = DeprecationLevel.HIDDEN)
     @get:JvmName("target")
     @get:JvmSynthetic
+    @OptIn(ExperimentalIdentification::class)
     open val target2: Any
         get() = target
 
@@ -247,6 +252,7 @@ sealed class OnlineMessageSource : MessageSource() {
     @Deprecated("for binary compatibility until 1.0.0", level = DeprecationLevel.HIDDEN)
     @get:JvmName("sender")
     @get:JvmSynthetic
+    @OptIn(ExperimentalIdentification::class)
     open val sender2: Any
         get() = sender
 }