diff --git a/homeassistant/components/assist_pipeline/__init__.py b/homeassistant/components/assist_pipeline/__init__.py
index f15657d5a91..f481411e551 100644
--- a/homeassistant/components/assist_pipeline/__init__.py
+++ b/homeassistant/components/assist_pipeline/__init__.py
@@ -31,6 +31,8 @@ from .pipeline import (
     async_create_default_pipeline,
     async_get_pipeline,
     async_get_pipelines,
+    async_migrate_engine,
+    async_run_migrations,
     async_setup_pipeline_store,
     async_update_pipeline,
 )
@@ -40,6 +42,7 @@ __all__ = (
     "DOMAIN",
     "async_create_default_pipeline",
     "async_get_pipelines",
+    "async_migrate_engine",
     "async_setup",
     "async_pipeline_from_audio_stream",
     "async_update_pipeline",
@@ -72,6 +75,7 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     hass.data[DATA_LAST_WAKE_UP] = {}
 
     await async_setup_pipeline_store(hass)
+    await async_run_migrations(hass)
     async_register_websocket_api(hass)
 
     return True
diff --git a/homeassistant/components/assist_pipeline/const.py b/homeassistant/components/assist_pipeline/const.py
index 3463d94fb84..36b72dad69c 100644
--- a/homeassistant/components/assist_pipeline/const.py
+++ b/homeassistant/components/assist_pipeline/const.py
@@ -3,6 +3,7 @@
 DOMAIN = "assist_pipeline"
 
 DATA_CONFIG = f"{DOMAIN}.config"
+DATA_MIGRATIONS = f"{DOMAIN}_migrations"
 
 DEFAULT_PIPELINE_TIMEOUT = 60 * 5  # seconds
 
diff --git a/homeassistant/components/assist_pipeline/pipeline.py b/homeassistant/components/assist_pipeline/pipeline.py
index 0d25950d65b..2251167466c 100644
--- a/homeassistant/components/assist_pipeline/pipeline.py
+++ b/homeassistant/components/assist_pipeline/pipeline.py
@@ -13,7 +13,7 @@ from pathlib import Path
 from queue import Empty, Queue
 from threading import Thread
 import time
-from typing import TYPE_CHECKING, Any, Final, cast
+from typing import TYPE_CHECKING, Any, Final, Literal, cast
 import wave
 
 import voluptuous as vol
@@ -56,6 +56,7 @@ from .const import (
     CONF_DEBUG_RECORDING_DIR,
     DATA_CONFIG,
     DATA_LAST_WAKE_UP,
+    DATA_MIGRATIONS,
     DOMAIN,
     WAKE_WORD_COOLDOWN,
 )
@@ -376,10 +377,6 @@ class Pipeline:
         This function was added in HA Core 2023.10, previous versions will raise
         if there are unexpected items in the serialized data.
         """
-        # Migrate to new value for conversation agent
-        if data["conversation_engine"] == conversation.OLD_HOME_ASSISTANT_AGENT:
-            data["conversation_engine"] = conversation.HOME_ASSISTANT_AGENT
-
         return cls(
             conversation_engine=data["conversation_engine"],
             conversation_language=data["conversation_language"],
@@ -1818,3 +1815,47 @@ async def async_setup_pipeline_store(hass: HomeAssistant) -> PipelineData:
         PIPELINE_FIELDS,
     ).async_setup(hass)
     return PipelineData(pipeline_store)
+
+
+@callback
+def async_migrate_engine(
+    hass: HomeAssistant,
+    engine_type: Literal["conversation", "stt", "tts", "wake_word"],
+    old_value: str,
+    new_value: str,
+) -> None:
+    """Register a migration of an engine used in pipelines."""
+    hass.data.setdefault(DATA_MIGRATIONS, {})[engine_type] = (old_value, new_value)
+
+    # Run migrations when config is already loaded
+    if DATA_CONFIG in hass.data:
+        hass.async_create_background_task(
+            async_run_migrations(hass), "assist_pipeline_migration", eager_start=True
+        )
+
+
+async def async_run_migrations(hass: HomeAssistant) -> None:
+    """Run pipeline migrations."""
+    if not (migrations := hass.data.get(DATA_MIGRATIONS)):
+        return
+
+    engine_attr = {
+        "conversation": "conversation_engine",
+        "stt": "stt_engine",
+        "tts": "tts_engine",
+        "wake_word": "wake_word_entity",
+    }
+
+    updates = []
+
+    for pipeline in async_get_pipelines(hass):
+        attr_updates = {}
+        for engine_type, (old_value, new_value) in migrations.items():
+            if getattr(pipeline, engine_attr[engine_type]) == old_value:
+                attr_updates[engine_attr[engine_type]] = new_value
+
+        if attr_updates:
+            updates.append((pipeline, attr_updates))
+
+    for pipeline, attr_updates in updates:
+        await async_update_pipeline(hass, pipeline, **attr_updates)
diff --git a/homeassistant/components/conversation/__init__.py b/homeassistant/components/conversation/__init__.py
index 63e0e9bff59..333fb24498b 100644
--- a/homeassistant/components/conversation/__init__.py
+++ b/homeassistant/components/conversation/__init__.py
@@ -43,8 +43,9 @@ __all__ = [
     "async_converse",
     "async_get_agent_info",
     "async_set_agent",
-    "async_unset_agent",
     "async_setup",
+    "async_unset_agent",
+    "ConversationEntity",
     "ConversationInput",
     "ConversationResult",
 ]
@@ -188,6 +189,15 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
         hass, entity_component, config.get(DOMAIN, {}).get("intents", {})
     )
 
+    # Temporary migration. We can remove this in 2024.10
+    from homeassistant.components.assist_pipeline import (  # pylint: disable=import-outside-toplevel
+        async_migrate_engine,
+    )
+
+    async_migrate_engine(
+        hass, "conversation", OLD_HOME_ASSISTANT_AGENT, HOME_ASSISTANT_AGENT
+    )
+
     async def handle_process(service: ServiceCall) -> ServiceResponse:
         """Parse text into commands."""
         text = service.data[ATTR_TEXT]
@@ -227,3 +237,15 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     async_setup_conversation_http(hass)
 
     return True
+
+
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Set up a config entry."""
+    component: EntityComponent[ConversationEntity] = hass.data[DOMAIN]
+    return await component.async_setup_entry(entry)
+
+
+async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Unload a config entry."""
+    component: EntityComponent[ConversationEntity] = hass.data[DOMAIN]
+    return await component.async_unload_entry(entry)
diff --git a/homeassistant/components/conversation/manifest.json b/homeassistant/components/conversation/manifest.json
index 76c5b5ad666..8ee27986bb8 100644
--- a/homeassistant/components/conversation/manifest.json
+++ b/homeassistant/components/conversation/manifest.json
@@ -5,7 +5,6 @@
   "dependencies": ["http", "intent"],
   "documentation": "https://www.home-assistant.io/integrations/conversation",
   "integration_type": "system",
-  "iot_class": "local_push",
   "quality_scale": "internal",
   "requirements": ["hassil==1.6.1", "home-assistant-intents==2024.4.3"]
 }
diff --git a/homeassistant/const.py b/homeassistant/const.py
index 0eed33c48d7..a9dbfef5eab 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -44,6 +44,7 @@ class Platform(StrEnum):
     CALENDAR = "calendar"
     CAMERA = "camera"
     CLIMATE = "climate"
+    CONVERSATION = "conversation"
     COVER = "cover"
     DATE = "date"
     DATETIME = "datetime"
diff --git a/script/hassfest/dependencies.py b/script/hassfest/dependencies.py
index d9ec114e5bb..6fe7700cb3f 100644
--- a/script/hassfest/dependencies.py
+++ b/script/hassfest/dependencies.py
@@ -156,6 +156,8 @@ IGNORE_VIOLATIONS = {
     ("websocket_api", "lovelace"),
     ("websocket_api", "shopping_list"),
     "logbook",
+    # Temporary needed for migration until 2024.10
+    ("conversation", "assist_pipeline"),
 }
 
 
diff --git a/tests/components/assist_pipeline/test_pipeline.py b/tests/components/assist_pipeline/test_pipeline.py
index 3588bba6416..cf3afff0172 100644
--- a/tests/components/assist_pipeline/test_pipeline.py
+++ b/tests/components/assist_pipeline/test_pipeline.py
@@ -19,6 +19,7 @@ from homeassistant.components.assist_pipeline.pipeline import (
     async_create_default_pipeline,
     async_get_pipeline,
     async_get_pipelines,
+    async_migrate_engine,
     async_update_pipeline,
 )
 from homeassistant.core import HomeAssistant
@@ -118,6 +119,12 @@ async def test_loading_pipelines_from_storage(
     hass: HomeAssistant, hass_storage: dict[str, Any]
 ) -> None:
     """Test loading stored pipelines on start."""
+    async_migrate_engine(
+        hass,
+        "conversation",
+        conversation.OLD_HOME_ASSISTANT_AGENT,
+        conversation.HOME_ASSISTANT_AGENT,
+    )
     id_1 = "01GX8ZWBAQYWNB1XV3EXEZ75DY"
     hass_storage[STORAGE_KEY] = {
         "version": STORAGE_VERSION,
@@ -614,3 +621,41 @@ async def test_update_pipeline(
         "wake_word_entity": "wake_work.test_1",
         "wake_word_id": "wake_word_id_1",
     }
+
+
+async def test_migrate_after_load(
+    hass: HomeAssistant, init_supporting_components
+) -> None:
+    """Test migrating an engine after done loading."""
+    assert await async_setup_component(hass, "assist_pipeline", {})
+
+    pipeline_data: PipelineData = hass.data[DOMAIN]
+    store = pipeline_data.pipeline_store
+    assert len(store.data) == 1
+
+    assert (
+        await async_create_default_pipeline(
+            hass,
+            stt_engine_id="bla",
+            tts_engine_id="bla",
+            pipeline_name="Bla pipeline",
+        )
+        is None
+    )
+    pipeline = await async_create_default_pipeline(
+        hass,
+        stt_engine_id="test",
+        tts_engine_id="test",
+        pipeline_name="Test pipeline",
+    )
+    assert pipeline is not None
+
+    async_migrate_engine(hass, "stt", "test", "stt.test")
+    async_migrate_engine(hass, "tts", "test", "tts.test")
+
+    await hass.async_block_till_done(wait_background_tasks=True)
+
+    pipeline_updated = async_get_pipeline(hass, pipeline.id)
+
+    assert pipeline_updated.stt_engine == "stt.test"
+    assert pipeline_updated.tts_engine == "tts.test"