diff --git a/matrix_puppeteer_line/db/__init__.py b/matrix_puppeteer_line/db/__init__.py
index 62784dc..dff5ef7 100644
--- a/matrix_puppeteer_line/db/__init__.py
+++ b/matrix_puppeteer_line/db/__init__.py
@@ -7,12 +7,13 @@ from .stranger import Stranger
 from .portal import Portal
 from .message import Message
 from .media import Media
+from .receipt import Receipt
 from .receipt_reaction import ReceiptReaction
 
 
 def init(db: Database) -> None:
-    for table in (User, Puppet, Stranger, Portal, Message, Media, ReceiptReaction):
+    for table in (User, Puppet, Stranger, Portal, Message, Media, Receipt, ReceiptReaction):
         table.db = db
 
 
-__all__ = ["upgrade_table", "User", "Puppet", "Stranger", "Portal", "Message", "Media", "ReceiptReaction"]
+__all__ = ["upgrade_table", "User", "Puppet", "Stranger", "Portal", "Message", "Media", "Receipt", "ReceiptReaction"]
diff --git a/matrix_puppeteer_line/db/message.py b/matrix_puppeteer_line/db/message.py
index d5b4a19..aa48b4f 100644
--- a/matrix_puppeteer_line/db/message.py
+++ b/matrix_puppeteer_line/db/message.py
@@ -13,7 +13,7 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from typing import Optional, ClassVar, Dict, TYPE_CHECKING
+from typing import Optional, ClassVar, Dict, List, TYPE_CHECKING
 
 from attr import dataclass
 
@@ -31,10 +31,11 @@ class Message:
     mx_room: RoomID
     mid: Optional[int]
     chat_id: str
+    is_outgoing: bool
 
     async def insert(self) -> None:
-        q = "INSERT INTO message (mxid, mx_room, mid, chat_id) VALUES ($1, $2, $3, $4)"
-        await self.db.execute(q, self.mxid, self.mx_room, self.mid, self.chat_id)
+        q = "INSERT INTO message (mxid, mx_room, mid, chat_id, is_outgoing) VALUES ($1, $2, $3, $4, $5)"
+        await self.db.execute(q, self.mxid, self.mx_room, self.mid, self.chat_id, self.is_outgoing)
 
     async def update_ids(self, new_mxid: EventID, new_mid: int) -> None:
         q = ("UPDATE message SET mxid=$1, mid=$2 "
@@ -55,6 +56,15 @@ class Message:
             data[row["chat_id"]] = row["max_mid"]
         return data
 
+    @classmethod
+    async def get_max_outgoing_mids(cls) -> Dict[str, int]:
+        rows = await cls.db.fetch("SELECT chat_id, MAX(mid) AS max_mid "
+                                  "FROM message WHERE is_outgoing GROUP BY chat_id")
+        data = {}
+        for row in rows:
+            data[row["chat_id"]] = row["max_mid"]
+        return data
+
     @classmethod
     async def get_num_noid_msgs(cls, room_id: RoomID) -> int:
         return await cls.db.fetchval("SELECT COUNT(*) FROM message "
@@ -74,7 +84,7 @@ class Message:
 
     @classmethod
     async def get_by_mxid(cls, mxid: EventID, mx_room: RoomID) -> Optional['Message']:
-        row = await cls.db.fetchrow("SELECT mxid, mx_room, mid, chat_id "
+        row = await cls.db.fetchrow("SELECT mxid, mx_room, mid, chat_id, is_outgoing "
                                     "FROM message WHERE mxid=$1 AND mx_room=$2", mxid, mx_room)
         if not row:
             return None
@@ -82,15 +92,22 @@ class Message:
 
     @classmethod
     async def get_by_mid(cls, mid: int) -> Optional['Message']:
-        row = await cls.db.fetchrow("SELECT mxid, mx_room, mid, chat_id FROM message WHERE mid=$1",
+        row = await cls.db.fetchrow("SELECT mxid, mx_room, mid, chat_id, is_outgoing FROM message WHERE mid=$1",
                                     mid)
         if not row:
             return None
         return cls(**row)
 
+    @classmethod
+    async def get_all_since(cls, chat_id: str, min_mid: int, max_mid: int) -> List['Message']:
+        rows = await cls.db.fetch("SELECT mxid, mx_room, mid, chat_id, is_outgoing FROM message "
+                                  "WHERE chat_id=$1 AND $2<mid AND mid<=$3",
+                                  chat_id, min_mid, max_mid)
+        return [cls(**row) for row in rows]
+
     @classmethod
     async def get_next_noid_msg(cls, room_id: RoomID) -> Optional['Message']:
-        row = await cls.db.fetchrow("SELECT mxid, mx_room, mid, chat_id FROM message "
+        row = await cls.db.fetchrow("SELECT mxid, mx_room, mid, chat_id, is_outgoing FROM message "
                                     "WHERE mid IS NULL AND mx_room=$1", room_id)
         if not row:
             return None
diff --git a/matrix_puppeteer_line/db/receipt.py b/matrix_puppeteer_line/db/receipt.py
new file mode 100644
index 0000000..3556f20
--- /dev/null
+++ b/matrix_puppeteer_line/db/receipt.py
@@ -0,0 +1,72 @@
+# matrix-puppeteer-line - A very hacky Matrix-LINE bridge based on running LINE's Chrome extension in Puppeteer
+# Copyright (C) 2020-2021 Tulir Asokan, Andrew Ferrazzutti
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+from typing import List, ClassVar, Dict, Optional, TYPE_CHECKING
+
+from attr import dataclass
+
+from mautrix.util.async_db import Database
+
+fake_db = Database("") if TYPE_CHECKING else None
+
+
+@dataclass
+class Receipt:
+    db: ClassVar[Database] = fake_db
+
+    mid: int
+    chat_id: str
+    num_read: int
+
+    async def insert_or_update(self) -> None:
+        q = ("INSERT INTO receipt (mid, chat_id, num_read) "
+             "VALUES ($1, $2, $3) "
+             "ON CONFLICT (chat_id, num_read) "
+             "DO UPDATE SET mid=EXCLUDED.mid, num_read=EXCLUDED.num_read")
+        await self.db.execute(q, self.mid, self.chat_id, self.num_read)
+
+        # Delete lower counts for earlier messages
+        # TODO Consider using a CHECK for this instead
+        q = ("DELETE FROM receipt "
+             "WHERE chat_id=$1 AND mid<$2 AND num_read<$3")
+        await self.db.execute(q, self.chat_id, self.mid, self.num_read)
+
+    @classmethod
+    async def get_max_mid(cls, chat_id: str, num_read: int) -> Optional[int]:
+        q = ("SELECT mid FROM receipt "
+             "WHERE chat_id=$1 AND num_read=$2")
+        return await cls.db.fetchval(q, chat_id, num_read)
+
+    @classmethod
+    async def get_max_mid_per_num_read(cls, chat_id: str) -> Dict[int, int]:
+        rows = await cls.db.fetch("SELECT chat_id, mid, num_read FROM receipt WHERE chat_id=$1", chat_id)
+        data = {}
+        for row in rows:
+            data[row["num_read"]] = row["mid"]
+        return data
+
+    @classmethod
+    async def get_max_mids_per_num_read(cls) -> Dict[str, Dict[int, int]]:
+        rows = await cls.db.fetch("SELECT chat_id, mid, num_read FROM receipt")
+        data = {}
+        for row in rows:
+            chat_id = row["chat_id"]
+            if chat_id not in data:
+                inner_data = {}
+                data[chat_id] = inner_data
+            else:
+                inner_data = data[chat_id]
+            inner_data[row["num_read"]] = row["mid"]
+        return data
diff --git a/matrix_puppeteer_line/db/upgrade.py b/matrix_puppeteer_line/db/upgrade.py
index 9fce3a9..ac98ee5 100644
--- a/matrix_puppeteer_line/db/upgrade.py
+++ b/matrix_puppeteer_line/db/upgrade.py
@@ -135,4 +135,31 @@ async def upgrade_strangers(conn: Connection) -> None:
 async def upgrade_noid_msgs(conn: Connection) -> None:
     await conn.execute("ALTER TABLE message DROP CONSTRAINT IF EXISTS message_pkey")
     await conn.execute("ALTER TABLE message ALTER COLUMN mid DROP NOT NULL")
-    await conn.execute("ALTER TABLE message ADD UNIQUE (mid)")
\ No newline at end of file
+
+    table_name = "message"
+    constraint_name = f"{table_name}_mid_key"
+    q = ( "SELECT EXISTS(SELECT FROM information_schema.constraint_table_usage "
+         f"WHERE table_name='{table_name}' AND constraint_name='{constraint_name}')")
+    has_constraint = await conn.fetchval(q)
+    if not has_constraint:
+        await conn.execute(f"ALTER TABLE {table_name} ADD UNIQUE (mid)")
+
+
+@upgrade_table.register(description="Track LINE read receipts")
+async def upgrade_latest_read_receipts(conn: Connection) -> None:
+    await conn.execute("ALTER TABLE message DROP CONSTRAINT IF EXISTS message_mid_key")
+    await conn.execute("ALTER TABLE message ADD UNIQUE (mid, chat_id)")
+    await conn.execute("ALTER TABLE message "
+                       "ADD COLUMN IF NOT EXISTS "
+                       "is_outgoing BOOLEAN NOT NULL DEFAULT false")
+
+    await conn.execute("""CREATE TABLE IF NOT EXISTS receipt (
+        mid      INTEGER NOT NULL,
+        chat_id  TEXT NOT NULL,
+        num_read INTEGER NOT NULL DEFAULT 1,
+
+        PRIMARY KEY (chat_id, num_read),
+        FOREIGN KEY (mid, chat_id)
+            REFERENCES message (mid, chat_id)
+            ON DELETE CASCADE
+    )""")
\ No newline at end of file
diff --git a/matrix_puppeteer_line/portal.py b/matrix_puppeteer_line/portal.py
index 26ac5e1..3ad5093 100644
--- a/matrix_puppeteer_line/portal.py
+++ b/matrix_puppeteer_line/portal.py
@@ -32,7 +32,7 @@ from mautrix.types import (EventID, MessageEventContent, RoomID, EventType, Mess
 from mautrix.errors import IntentError
 from mautrix.util.simple_lock import SimpleLock
 
-from .db import Portal as DBPortal, Message as DBMessage, ReceiptReaction as DBReceiptReaction, Media as DBMedia
+from .db import Portal as DBPortal, Message as DBMessage, Receipt as DBReceipt, ReceiptReaction as DBReceiptReaction, Media as DBMedia
 from .config import Config
 from .rpc import ChatInfo, Participant, Message, Receipt, Client, PathImage
 from .rpc.types import RPCError
@@ -173,7 +173,7 @@ class Portal(DBPortal, BasePortal):
         msg = None
         if message_id != -1:
             try:
-                msg = DBMessage(mxid=event_id, mx_room=self.mxid, mid=message_id, chat_id=self.chat_id)
+                msg = DBMessage(mxid=event_id, mx_room=self.mxid, mid=message_id, chat_id=self.chat_id, is_outgoing=True)
                 await msg.insert()
                 await self._send_delivery_receipt(event_id)
                 self.log.debug(f"Handled Matrix message {event_id} -> {message_id}")
@@ -211,7 +211,7 @@ class Portal(DBPortal, BasePortal):
                 intent = None
         return intent
 
-    async def handle_remote_message(self, source: 'u.User', evt: Message) -> None:
+    async def handle_remote_message(self, source: 'u.User', evt: Message, handle_receipt: bool = True) -> None:
         if await DBMessage.get_by_mid(evt.id):
             self.log.debug(f"Ignoring duplicate message {evt.id}")
             return
@@ -371,11 +371,8 @@ class Portal(DBPortal, BasePortal):
                 content.set_edit(prev_event_id)
             event_id = await self._send_message(intent, content, timestamp=evt.timestamp)
 
-        if evt.is_outgoing and evt.receipt_count:
-            await self._handle_receipt(event_id, evt.receipt_count)
-
         if not msg:
-            msg = DBMessage(mxid=event_id, mx_room=self.mxid, mid=evt.id, chat_id=self.chat_id)
+            msg = DBMessage(mxid=event_id, mx_room=self.mxid, mid=evt.id, chat_id=self.chat_id, is_outgoing=evt.is_outgoing)
             try:
                 await msg.insert()
                 #await self._send_delivery_receipt(event_id)
@@ -386,32 +383,56 @@ class Portal(DBPortal, BasePortal):
             await msg.update_ids(new_mxid=event_id, new_mid=evt.id)
             self.log.debug(f"Handled preseen remote message {evt.id} -> {event_id}")
 
+        if handle_receipt and evt.is_outgoing and evt.receipt_count:
+            await self._handle_receipt(event_id, evt.id, evt.receipt_count)
+
     async def handle_remote_receipt(self, receipt: Receipt) -> None:
         msg = await DBMessage.get_by_mid(receipt.id)
         if msg:
-            await self._handle_receipt(msg.mxid, receipt.count)
+            await self._handle_receipt(msg.mxid, receipt.id, receipt.count)
         else:
             self.log.debug(f"Could not find message for read receipt {receipt.id}")
 
-    async def _handle_receipt(self, event_id: EventID, receipt_count: int) -> None:
+    async def _handle_receipt(self, event_id: EventID, receipt_id: int, receipt_count: int) -> None:
         if self.is_direct:
             await self.main_intent.send_receipt(self.mxid, event_id)
         else:
-            reaction = await DBReceiptReaction.get_by_relation(event_id, self.mxid)
-            if reaction:
-                await self.main_intent.redact(self.mxid, reaction.mxid)
-                await reaction.delete()
+            # Update receipts not only for this message, but also for
+            # all messages before it with an equivalent "read by" count.
+            prev_receipt_id = await DBReceipt.get_max_mid(self.chat_id, receipt_count) or 0
+            messages = await DBMessage.get_all_since(self.chat_id, prev_receipt_id, receipt_id)
+
+            # Remove reactions for outdated "read by" counts.
+            for message in messages:
+                reaction = await DBReceiptReaction.get_by_relation(message.mxid, self.mxid)
+                if reaction:
+                    await self.main_intent.redact(self.mxid, reaction.mxid)
+                    await reaction.delete()
+
             # If there are as many receipts as there are chat participants, then everyone
             # must have read the message, so send real read receipts from each puppet.
             # TODO Not just -1 if there are multiple _OWN_ puppets...
-            if receipt_count == len(self._last_participant_update) - 1:
+            is_fully_read = receipt_count >= len(self._last_participant_update) - 1
+            if is_fully_read:
                 for mid in filter(lambda mid: not p.Puppet.is_mid_for_own_puppet(mid), self._last_participant_update):
                     intent = (await p.Puppet.get_by_mid(mid)).intent
                     await intent.send_receipt(self.mxid, event_id)
             else:
-                # TODO Translatable string for "Read by"
-                reaction_mxid = await self.main_intent.react(self.mxid, event_id, f"(Read by {receipt_count})")
-                await DBReceiptReaction(reaction_mxid, self.mxid, event_id, receipt_count).insert()
+                # TODO messages list should exclude non-outgoing messages,
+                #     but include them just to get rid of potential stale reactions
+                for message in (msg for msg in messages if msg.is_outgoing):
+                    # TODO Translatable string for "Read by"
+                    try:
+                        reaction_mxid = await self.main_intent.react(self.mxid, message.mxid, f"(Read by {receipt_count})")
+                        await DBReceiptReaction(reaction_mxid, self.mxid, message.mxid, receipt_count).insert()
+                    except Exception as e:
+                        self.log.warning(f"Failed to send read receipt reaction for message {message.mxid} in {self.chat_id}: {e}")
+
+        try:
+            await DBReceipt(mid=receipt_id, chat_id=self.chat_id, num_read=receipt_count).insert_or_update()
+            self.log.debug(f"Handled read receipt for message {receipt_id} read by {receipt_count}")
+        except Exception as e:
+            self.log.debug(f"Failed to handle read receipt for message {receipt_id} read by {receipt_count}: {e}")
 
     async def _handle_remote_media(self, source: 'u.User', intent: IntentAPI,
                                         media_url: str, media_id: Optional[str] = None,
@@ -581,31 +602,54 @@ class Portal(DBPortal, BasePortal):
                 await self.main_intent.kick_user(self.mxid, user_id,
                                                  reason="Kicking own puppet")
 
-    async def backfill(self, source: 'u.User') -> None:
+    async def backfill(self, source: 'u.User', info: ChatInfo) -> None:
         try:
             with self.backfill_lock:
-                await self._backfill(source)
+                await self._backfill(source, info)
         except Exception:
             self.log.exception("Failed to backfill portal")
 
-    async def _backfill(self, source: 'u.User') -> None:
+    async def _backfill(self, source: 'u.User', info: ChatInfo) -> None:
         self.log.debug("Backfilling history through %s", source.mxid)
 
+        events = await source.client.get_messages(self.chat_id)
+
         max_mid = await DBMessage.get_max_mid(self.mxid) or 0
-        messages = [msg for msg in await source.client.get_messages(self.chat_id)
+        messages = [msg for msg in events.messages
                     if msg.id > max_mid]
 
         if not messages:
-            self.log.debug("Didn't get any entries from server")
+            self.log.debug("Didn't get any messages from server")
+        else:
+            self.log.debug("Got %d messages from server", len(messages))
+            async with NotificationDisabler(self.mxid, source):
+                for evt in messages:
+                    await self.handle_remote_message(source, evt, handle_receipt=self.is_direct)
+            self.log.info("Backfilled %d messages through %s", len(messages), source.mxid)
             await self._cleanup_noid_msgs()
-            return
 
-        self.log.debug("Got %d messages from server", len(messages))
-        async with NotificationDisabler(self.mxid, source):
+
+        if not self.is_direct:
+            # Update participants before sending any receipts
+            # TODO Joins and leaves are (usually) shown after all, so track them properly.
+            #      In the meantime, just check the participants list after backfilling.
+            await self._update_participants(info.participants)
             for evt in messages:
-                await self.handle_remote_message(source, evt)
-        self.log.info("Backfilled %d messages through %s", len(messages), source.mxid)
-        await self._cleanup_noid_msgs()
+                if evt.is_outgoing and evt.receipt_count:
+                    await self.handle_remote_message(source, evt, handle_receipt=False)
+
+
+        max_mid_per_num_read = await DBReceipt.get_max_mid_per_num_read(self.chat_id)
+        receipts = [rct for rct in events.receipts
+                    if rct.id > max_mid_per_num_read.get(rct.count, 0)]
+
+        if not receipts:
+            self.log.debug("Didn't get any receipts from server")
+        else:
+            self.log.debug("Got %d receipts from server", len(receipts))
+            for rct in receipts:
+                await self.handle_remote_receipt(rct)
+            self.log.info("Backfilled %d receipts through %s", len(receipts), source.mxid)
 
     @property
     def bridge_info_state_key(self) -> str:
@@ -661,8 +705,7 @@ class Portal(DBPortal, BasePortal):
             await puppet.intent.ensure_joined(self.mxid)
 
         await self.update_info(info, source.client)
-        await self.backfill(source)
-        await self._update_participants(info.participants)
+        await self.backfill(source, info)
 
     async def _create_matrix_room(self, source: 'u.User', info: ChatInfo) -> Optional[RoomID]:
         if self.mxid:
@@ -741,11 +784,7 @@ class Portal(DBPortal, BasePortal):
             await self.update()
             self.log.debug(f"Matrix room created: {self.mxid}")
             self.by_mxid[self.mxid] = self
-            await self.backfill(source)
-            if not self.is_direct:
-                # TODO Joins and leaves are (usually) shown after all, so track them properly.
-                #      In the meantime, just check the participants list after backfilling.
-                await self._update_participants(info.participants)
+            await self.backfill(source, info)
 
         return self.mxid
 
diff --git a/matrix_puppeteer_line/rpc/client.py b/matrix_puppeteer_line/rpc/client.py
index d2e00ed..5897da8 100644
--- a/matrix_puppeteer_line/rpc/client.py
+++ b/matrix_puppeteer_line/rpc/client.py
@@ -19,7 +19,7 @@ from base64 import b64decode
 import asyncio
 
 from .rpc import RPCClient
-from .types import ChatListInfo, ChatInfo, ImageData, Message, Participant, Receipt, StartStatus
+from .types import ChatEvents, ChatListInfo, ChatInfo, ImageData, Message, Participant, Receipt, StartStatus
 
 
 class LoginCommand(TypedDict):
@@ -51,9 +51,8 @@ class Client(RPCClient):
     async def get_chat(self, chat_id: str, force_view: bool = False) -> ChatInfo:
         return ChatInfo.deserialize(await self.request("get_chat", chat_id=chat_id, force_view=force_view))
 
-    async def get_messages(self, chat_id: str) -> List[Message]:
-        resp = await self.request("get_messages", chat_id=chat_id)
-        return [Message.deserialize(data) for data in resp]
+    async def get_messages(self, chat_id: str) -> ChatEvents:
+        return ChatEvents.deserialize(await self.request("get_messages", chat_id=chat_id))
 
     async def read_image(self, image_url: str) -> ImageData:
         resp = await self.request("read_image", image_url=image_url)
@@ -86,8 +85,8 @@ class Client(RPCClient):
         resp = await self.request("send_file", chat_id=chat_id, file_path=file_path)
         return resp["id"]
 
-    async def set_last_message_ids(self, msg_ids: Dict[str, int]) -> None:
-        await self.request("set_last_message_ids", msg_ids=msg_ids)
+    async def set_last_message_ids(self, msg_ids: Dict[str, int], own_msg_ids: Dict[str, int], rct_ids: Dict[str, Dict[int, int]]) -> None:
+        await self.request("set_last_message_ids", msg_ids=msg_ids, own_msg_ids=own_msg_ids, rct_ids=rct_ids)
 
     async def on_message(self, func: Callable[[Message], Awaitable[None]]) -> None:
         async def wrapper(data: Dict[str, Any]) -> None:
diff --git a/matrix_puppeteer_line/rpc/types.py b/matrix_puppeteer_line/rpc/types.py
index e6f32d1..32e7711 100644
--- a/matrix_puppeteer_line/rpc/types.py
+++ b/matrix_puppeteer_line/rpc/types.py
@@ -77,6 +77,12 @@ class Receipt(SerializableAttrs['Receipt']):
     count: int = 1
 
 
+@dataclass
+class ChatEvents(SerializableAttrs['ChatEvents']):
+    messages: List[Message]
+    receipts: List[Receipt]
+
+
 @dataclass
 class ImageData:
     mime: str
diff --git a/matrix_puppeteer_line/user.py b/matrix_puppeteer_line/user.py
index b43e83a..24fef52 100644
--- a/matrix_puppeteer_line/user.py
+++ b/matrix_puppeteer_line/user.py
@@ -22,7 +22,7 @@ from mautrix.types import UserID, RoomID
 from mautrix.appservice import AppService, IntentAPI
 from mautrix.util.opt_prometheus import Gauge
 
-from .db import User as DBUser, Portal as DBPortal, Message as DBMessage
+from .db import User as DBUser, Portal as DBPortal, Message as DBMessage, Receipt as DBReceipt
 from .config import Config
 from .rpc import Client, Message, Receipt
 from . import puppet as pu, portal as po
@@ -135,7 +135,10 @@ class User(DBUser, BaseUser):
         self._connection_check_task = self.loop.create_task(self._check_connection_loop())
         await self.client.pause()
         await self.sync_own_profile()
-        await self.client.set_last_message_ids(await DBMessage.get_max_mids())
+        await self.client.set_last_message_ids(
+            await DBMessage.get_max_mids(),
+            await DBMessage.get_max_outgoing_mids(),
+            await DBReceipt.get_max_mids_per_num_read())
         limit = self.config["bridge.initial_conversation_sync"]
         self.log.info("Syncing chats")
         await self.send_bridge_notice("Synchronizing chats...")
@@ -186,7 +189,10 @@ class User(DBUser, BaseUser):
         self.log.trace("Received message %s", evt)
         portal = await po.Portal.get_by_chat_id(evt.chat_id, create=True)
         if not portal.mxid:
-            await self.client.set_last_message_ids(await DBMessage.get_max_mids())
+            await self.client.set_last_message_ids(
+                await DBMessage.get_max_mids(),
+                await DBMessage.get_max_outgoing_mids(),
+                await DBReceipt.get_max_mids_per_num_read())
             chat_info = await self.client.get_chat(evt.chat_id)
             await portal.create_matrix_room(self, chat_info)
         await portal.handle_remote_message(self, evt)
diff --git a/puppet/src/client.js b/puppet/src/client.js
index 94a74ed..5193ff6 100644
--- a/puppet/src/client.js
+++ b/puppet/src/client.js
@@ -257,7 +257,7 @@ export default class Client {
 				cancel_login: () => this.puppet.cancelLogin(),
 				send: req => this.puppet.sendMessage(req.chat_id, req.text),
 				send_file: req => this.puppet.sendFile(req.chat_id, req.file_path),
-				set_last_message_ids: req => this.puppet.setLastMessageIDs(req.msg_ids),
+				set_last_message_ids: req => this.puppet.setLastMessageIDs(req.msg_ids, req.own_msg_ids, req.rct_ids),
 				pause: () => this.puppet.stopObserving(),
 				resume: () => this.puppet.startObserving(),
 				get_own_profile: () => this.puppet.getOwnProfile(),
diff --git a/puppet/src/contentscript.js b/puppet/src/contentscript.js
index 428da3b..09d3cfc 100644
--- a/puppet/src/contentscript.js
+++ b/puppet/src/contentscript.js
@@ -64,11 +64,6 @@ window.__mautrixReceivePIN = function (pin) {}
  * @return {Promise<void>}
  */
 window.__mautrixExpiry = function (button) {}
-/**
- * @param {number} id - The ID of the message that was sent
- * @return {Promise<void>}
- */
-window.__mautrixReceiveMessageID = function(id) {}
 /**
  * @return {void}
  */
@@ -489,6 +484,13 @@ class MautrixController {
 		return this.ownMsgPromise ? await this.ownMsgPromise : -1
 	}
 
+	/**
+	 * @typedef ChatEvents
+	 * @type {object}
+	 * @property {MessageData[]} messages - All synced messages, which include receipts for them (if any).
+	 * @property {ReceiptData[]} receipts - All synced receipts for messages already present.
+	 */
+
 	/**
 	 * Parse the message list of whatever the currently-viewed chat is.
 	 *
@@ -521,6 +523,61 @@ class MautrixController {
 		.map(value => value.value)
 	}
 
+	/**
+	 * Parse receipts of whatever the currently-viewed chat is.
+	 * Should only be used for already-processed messages that
+	 * get skipped by parseMessageList.
+	 *
+	 * @param {?Object} rctIDs - The minimum receipt ID to consider for each "read by" count.
+	 *                           It's an Object because Puppeteer can't send a Map.
+	 * @return {ReceiptData[]} - A list of receipts.
+	 */
+	parseReceiptList(rctIDs = {}) {
+		console.debug(`rctIDs for full refresh: ${rctIDs}`)
+
+		const isDirect = this.getChatType(this.getCurrentChatID()) == ChatTypeEnum.DIRECT
+		const numOthers = isDirect ? 1 : document.querySelector(SEL_PARTICIPANTS_LIST).childElementCount - 1
+
+		const idGetter = e => +e.closest("[data-local-id]").getAttribute("data-local-id")
+
+		const receipts =
+			Array.from(document.querySelectorAll("#_chat_room_msg_list .mdRGT07Read:not(.MdNonDisp)"))
+			.map(isDirect
+				? e => {
+					return {
+						id: idGetter(e),
+						count: 1
+					}
+				}
+				: e => {
+					return {
+						id: idGetter(e),
+						count: this._getReceiptCount(e)
+					}
+				}
+				// Using two lambdas to not branch on isDirect for every element
+			)
+
+		const newReceipts = []
+		const prevFullyReadID = rctIDs[`${numOthers}`] || 0
+		let minCountToFind = 1
+		for (let i = receipts.length-1; i >= 0; i--) {
+			const receipt = receipts[i]
+			if (receipt.count >= minCountToFind && receipt.id > (rctIDs[`${receipt.count}`] || 0)) {
+				newReceipts.push(receipt)
+				if (receipt.count < numOthers) {
+					minCountToFind = receipt.count+1
+				} else {
+					break
+				}
+			} else if (receipt.id <= prevFullyReadID) {
+				break
+			}
+		}
+
+		return newReceipts
+	}
+
 	/**
 	 * @typedef PathImage
 	 * @type object
@@ -611,6 +668,16 @@ class MautrixController {
 	 *                                        signified by the number in its notification badge.
 	 */
 
+	/**
+	 * @typedef ChatListInfoForCycle
+	 * @type object
+	 * @property {number} id      - The ID of the chat.
+	 * @property {number} notificationCount - The number of unread messages in the chat,
+	 *                                        signified by the number in its notification badge.
+	 * @property {number} numParticipants - The number of participants in the chat,
+	 *                                      signified by a count next to the chat title.
+	 */
+
 	getChatListItemID(element) {
 		return element.getAttribute("data-chatid")
 	}
@@ -635,6 +702,12 @@ class MautrixController {
 		return Number.parseInt(element.querySelector(".MdIcoBadge01:not(.MdNonDisp)")?.innerText) || 0
 	}
 
+	getChatListItemOtherParticipantCount(element) {
+		const countElement = element.querySelector(".mdCMN04Count:not(.MdNonDisp)")
+		const match = countElement?.innerText.match(/\d+/)
+		return match ? match[0] - 1 : 1
+	}
+
 	/**
 	 * Parse a conversation list item element.
 	 *
@@ -664,6 +737,32 @@ class MautrixController {
 			child => this.parseChatListItem(child.firstElementChild))
 	}
 
+	/**
+	 * Parse a conversation list item element for cycling.
+	 *
+	 * @param {Element} element - The element to parse.
+	 * @return {ChatListInfoForCycle} - The info in the element.
+	 */
+	parseChatListItemForCycle(element) {
+		return {
+			id: this.getChatListItemID(element),
+			notificationCount: this.getChatListItemNotificationCount(element),
+			otherParticipantCount: this.getChatListItemOtherParticipantCount(element),
+		}
+	}
+
+	/**
+	 * Parse the list of recent/saved chats, but for properties
+	 * relevant to knowing which chat to cycle onto for read receipts.
+	 *
+	 * @return {ChatListInfoForCycle[]} - The list of chats with relevant properties.
+	 */
+	parseChatListForCycle() {
+		const chatList = document.querySelector("#_chat_list_body")
+		return Array.from(chatList.children).map(
+			child => this.parseChatListItemForCycle(child.firstElementChild))
+	}
+
 	/**
 	 * Download an image at a given URL and return it as a data URL.
 	 *
@@ -800,7 +899,14 @@ class MautrixController {
 	}
 
 	/**
-	 * @param {[MutationRecord]} mutations - The mutation records that occurred
+	 * @typedef ReceiptData
+	 * @type {object}
+	 * @property {number}  id     - The ID of the read message.
+	 * @property {?number} count  - The number of users who have read the message.
+	 */
+
+	/**
+	 * @param {MutationRecord[]} mutations - The mutation records that occurred
 	 * @param {string} chatID - The ID of the chat being observed.
 	 * @private
 	 */
@@ -1182,8 +1288,7 @@ class MautrixController {
 		const resolve = this.promiseOwnMsgResolve
 		this._promiseOwnMsgReset()
 
-		window.__mautrixReceiveMessageID(msgID).then(
-			() => resolve(msgID))
+		resolve(msgID)
 	}
 
 	_rejectOwnMessage(failureElement = null) {
diff --git a/puppet/src/puppet.js b/puppet/src/puppet.js
index 7c8ab71..e031b7a 100644
--- a/puppet/src/puppet.js
+++ b/puppet/src/puppet.js
@@ -46,9 +46,11 @@ export default class MessagesPuppeteer {
 		this.sendPlaceholders = sendPlaceholders
 		this.profilePath = profilePath
 		this.updatedChats = new Set()
-		this.sentMessageIDs = new Set()
 		this.mostRecentMessages = new Map()
+		this.mostRecentOwnMessages = new Map()
+		this.mostRecentReceipts = new Map()
 		this.numChatNotifications = new Map()
+		this.cycleTimerID = null
 		this.taskQueue = new TaskQueue(this.id)
 		this.client = client
 	}
@@ -105,8 +107,6 @@ export default class MessagesPuppeteer {
 		await this.page.exposeFunction("__mautrixReceiveQR", this._receiveQRChange.bind(this))
 		await this.page.exposeFunction("__mautrixSendEmailCredentials", this._sendEmailCredentials.bind(this))
 		await this.page.exposeFunction("__mautrixReceivePIN", this._receivePIN.bind(this))
-		await this.page.exposeFunction("__mautrixReceiveMessageID",
-			id => this.sentMessageIDs.add(id))
 		await this.page.exposeFunction("__mautrixReceiveChanges",
 			this._receiveChatListChanges.bind(this))
 		await this.page.exposeFunction("__mautrixReceiveMessages",
@@ -424,19 +424,40 @@ export default class MessagesPuppeteer {
 	 * Get messages in a chat.
 	 *
 	 * @param {string} chatID The ID of the chat whose messages to get.
-	 * @return {Promise<[MessageData]>} - The messages visible in the chat.
+	 * @return {Promise<ChatEvents>} - New messages and receipts synced fron the chat.
 	 */
 	async getMessages(chatID) {
 		return await this.taskQueue.push(() => this._getMessagesUnsafe(chatID))
 	}
 
-	setLastMessageIDs(ids) {
+	setLastMessageIDs(msgIDs, ownMsgIDs, rctIDs) {
 		this.mostRecentMessages.clear()
-		for (const [chatID, messageID] of Object.entries(ids)) {
+		for (const [chatID, messageID] of Object.entries(msgIDs)) {
 			this.mostRecentMessages.set(chatID, messageID)
 		}
 		this.log("Updated most recent message ID map:")
-		this.log(JSON.stringify(this.mostRecentMessages))
+		this.log(JSON.stringify(msgIDs))
+
+		for (const [chatID, messageID] of Object.entries(ownMsgIDs)) {
+			this.mostRecentOwnMessages.set(chatID, messageID)
+		}
+		this.log("Updated most recent own message ID map:")
+		this.log(JSON.stringify(ownMsgIDs))
+
+		this.mostRecentReceipts.clear()
+		for (const [chatID, receipts] of Object.entries(rctIDs)) {
+			const receiptMap = this._getReceiptMap(chatID)
+			for (const [count, receiptID] of Object.entries(receipts)) {
+				receiptMap.set(+count, receiptID)
+			}
+		}
+		this.log("Updated most recent receipt ID map")
+		for (const [chatID, receiptMap] of this.mostRecentReceipts) {
+			this.log(`${chatID}:`)
+			for (const [count, receiptID] of receiptMap) {
+				this.log(`Read by ${count}: ${receiptID}`)
+			}
+		}
 	}
 
 	async readImage(imageUrl) {
@@ -450,9 +471,69 @@ export default class MessagesPuppeteer {
 		return { id: await this.taskQueue.push(() => this._sendFileUnsafe(chatID, filePath)) }
 	}
 
+	_cycleTimerStart() {
+		// TODO Config for cycle delay
+		this.cycleTimerID = setTimeout(
+			() => this.taskQueue.push(() => this._cycleChatUnsafe()),
+			5000)
+	}
+
+	async _cycleChatUnsafe() {
+		const currentChatID = await this.page.evaluate(() => window.__mautrixController.getCurrentChatID())
+		const chatList = await this.page.evaluate(() => window.__mautrixController.parseChatListForCycle())
+		// Add 1 to start at the chat after the currently-viewed one
+		const offset = 1 + Math.max(chatList.findIndex(item => item.id == currentChatID), 0)
+
+		// Visit next chat for which:
+		// - there are no unread notifications
+		// - the most recently-sent own message is not fully read
+		let chatIDToSync
+		for (let i = 0, n = chatList.length; i < n; i++) {
+			const chatListItem = chatList[(i+offset) % n]
+
+			if (chatListItem.notificationCount > 0) {
+				// Chat has unread notifications, so don't view it
+				continue
+			}
+
+			if (chatListItem.otherParticipantCount == 0) {
+				// Chat has no other participants (must be a non-DM with only you), so nothing to sync
+				continue
+			}
+
+			const mostRecentOwnMsgID = this.mostRecentOwnMessages.get(chatListItem.id)
+			if (mostRecentOwnMsgID == undefined) {
+				// Chat doesn't have any own messages, so no need to view it
+				continue
+			}
+
+			const receiptMap = this._getReceiptMap(chatListItem.id)
+			const mostRecentFullyReadMsgID = receiptMap.get(chatListItem.otherParticipantCount)
+			if (mostRecentFullyReadMsgID == mostRecentOwnMsgID) {
+				// Latest own message is fully-read, nothing to see here, move along
+				continue
+			}
+
+			chatIDToSync = chatListItem.id
+			break
+		}
+
+		if (!chatIDToSync) {
+			// TODO Confirm if this actually works...!
+			this.log(`Found no chats in need of read receipt updates, so force-viewing ${currentChatID} just to keep LINE alive`)
+			await this._switchChat(currentChatID, true)
+		} else {
+			this.log(`Viewing chat ${chatIDToSync} to check for new read receipts`)
+			await this._syncChat(chatIDToSync)
+		}
+
+		this._cycleTimerStart()
+	}
+
 	async startObserving() {
+		// TODO Highly consider syncing anything that was missed since stopObserving...
 		const chatID = await this.page.evaluate(() => window.__mautrixController.getCurrentChatID())
-		this.log(`Adding observers for ${chatID || "empty chat"}`)
+		this.log(`Adding observers for ${chatID || "empty chat"}, and global timers`)
 		await this.page.evaluate(
 			() => window.__mautrixController.addChatListObserver())
 		if (chatID) {
@@ -460,14 +541,23 @@ export default class MessagesPuppeteer {
 				(mostRecentMessage) => window.__mautrixController.addMsgListObserver(mostRecentMessage),
 				this.mostRecentMessages.get(chatID))
 		}
+
+		if (this.cycleTimerID == null) {
+			this._cycleTimerStart()
+		}
 	}
 
 	async stopObserving() {
-		this.log("Removing observers")
+		this.log("Removing observers and timers")
 		await this.page.evaluate(
 			() => window.__mautrixController.removeChatListObserver())
 		await this.page.evaluate(
 			() => window.__mautrixController.removeMsgListObserver())
+
+		if (this.cycleTimerID != null) {
+			clearTimeout(this.cycleTimerID)
+			this.cycleTimerID = null
+		}
 	}
 
 	async getOwnProfile() {
@@ -651,7 +741,7 @@ export default class MessagesPuppeteer {
 
 	async _sendMessageUnsafe(chatID, text) {
 		// Sync all messages in this chat first
-		this._receiveMessages(chatID, await this._getMessagesUnsafe(chatID), true)
+		await this._syncChat(chatID)
 		// TODO Initiate the promise in the content script
 		await this.page.evaluate(
 			() => window.__mautrixController.promiseOwnMessage(5000, "time"))
@@ -670,7 +760,7 @@ export default class MessagesPuppeteer {
 	}
 
 	async _sendFileUnsafe(chatID, filePath) {
-		this._receiveMessages(chatID, await this._getMessagesUnsafe(chatID), true)
+		await this._syncChat(chatID)
 		await this.page.evaluate(
 			() => window.__mautrixController.promiseOwnMessage(
 				10000, // Use longer timeout for file uploads
@@ -701,6 +791,8 @@ export default class MessagesPuppeteer {
 			const id = await this.page.evaluate(
 				() => window.__mautrixController.waitForOwnMessage())
 			this.log(`Successfully sent message ${id} to ${chatID}`)
+			this.mostRecentMessages.set(chatID, id)
+			this.mostRecentOwnMessages.set(chatID, id)
 			return id
 		} catch (e) {
 			// TODO Catch if something other than a timeout
@@ -712,10 +804,10 @@ export default class MessagesPuppeteer {
 	}
 
 	_receiveMessages(chatID, messages, skipProcessing = false) {
+		if (!skipProcessing) {
+			messages = this._processMessages(chatID, messages)
+		}
 		if (this.client) {
-			if (!skipProcessing) {
-				messages = this._processMessages(chatID, messages)
-			}
 			for (const message of messages) {
 				this.client.sendMessage(message).catch(err =>
 					this.error("Failed to send message", message.id, "to client:", err))
@@ -737,12 +829,45 @@ export default class MessagesPuppeteer {
 		await this._switchChat(chatID)
 		// TODO Is it better to reset the notification count in _switchChat instead of here?
 		this.numChatNotifications.set(chatID, 0)
+
+
 		let messages = await this.page.evaluate(
 			mostRecentMessage => window.__mautrixController.parseMessageList(mostRecentMessage),
 			this.mostRecentMessages.get(chatID))
 		// Doing this before restoring the observer since it updates minID
 		messages = this._processMessages(chatID, messages)
 
+
+		const receiptMap = this._getReceiptMap(chatID)
+
+		// Sync receipts seen from newly-synced messages
+		// TODO When user leaves, clear the read-by count for the old number of other participants
+		let minCountToFind = 1
+		for (let i = messages.length-1; i >= 0; i--) {
+			const message = messages[i]
+			if (!message.is_outgoing) {
+				continue
+			}
+			const count = message.receipt_count
+			if (count >= minCountToFind && message.id > (receiptMap.get(count) || 0)) {
+				minCountToFind = count+1
+				receiptMap.set(count, message.id)
+			}
+			// TODO Early exit when count == num other participants
+		}
+
+		// Sync receipts from previously-seen messages
+		const receipts = await this.page.evaluate(
+			mostRecentReceipts => window.__mautrixController.parseReceiptList(mostRecentReceipts),
+			Object.fromEntries(receiptMap))
+		for (const receipt of receipts) {
+			receiptMap.set(receipt.count, receipt.id)
+			receipt.chat_id = chatID
+		}
+
+		this._trimReceiptMap(receiptMap)
+
+
 		if (hadMsgListObserver) {
 			this.log("Restoring msg list observer")
 			await this.page.evaluate(
@@ -752,13 +877,16 @@ export default class MessagesPuppeteer {
 			this.log("Not restoring msg list observer, as there never was one")
 		}
 
-		return messages
+		return {
+			messages: messages,
+			receipts: receipts
+		}
 	}
 
 	_processMessages(chatID, messages) {
 		// TODO Probably don't need minID filtering if Puppeteer context handles it now
 		const minID = this.mostRecentMessages.get(chatID) || 0
-		const filteredMessages = messages.filter(msg => msg.id > minID && !this.sentMessageIDs.has(msg.id))
+		const filteredMessages = messages.filter(msg => msg.id > minID)
 
 		if (filteredMessages.length > 0) {
 			const newFirstID = filteredMessages[0].id
@@ -769,12 +897,40 @@ export default class MessagesPuppeteer {
 			for (const message of filteredMessages) {
 				message.chat_id = chatID
 			}
+			for (let i = filteredMessages.length - 1; i >= 0; i--) {
+				const message = filteredMessages[i]
+				if (message.is_outgoing) {
+					this.mostRecentOwnMessages.set(chatID, message.id)
+					break
+				}
+			}
 			return filteredMessages
 		} else {
 			return []
 		}
 	}
 
+	_getReceiptMap(chatID) {
+		if (!this.mostRecentReceipts.has(chatID)) {
+			const newMap = new Map()
+			this.mostRecentReceipts.set(chatID, newMap)
+			return newMap
+		} else {
+			return this.mostRecentReceipts.get(chatID)
+		}
+	}
+
+	_trimReceiptMap(receiptMap) {
+		// Delete lower counts for earlier messages
+		let prevCount = null
+		for (const count of Array.from(receiptMap.keys()).sort()) {
+			if (prevCount != null && receiptMap.get(prevCount) < receiptMap.get(count)) {
+				receiptMap.delete(count)
+			}
+			prevCount = count
+		}
+	}
+
 	async _processChatListChangeUnsafe(chatListInfo) {
 		const chatID = chatListInfo.id
 		this.updatedChats.delete(chatID)
@@ -818,22 +974,26 @@ export default class MessagesPuppeteer {
 				html: chatListInfo.lastMsg,
 			}]
 			this.numChatNotifications.set(chatID, chatListInfo.notificationCount)
+			this._receiveMessages(chatID, messages, true)
 		} else {
-			messages = await this._getMessagesUnsafe(chatListInfo.id)
 			this.numChatNotifications.set(chatID, 0)
-			if (messages.length === 0) {
-				this.log("No new messages found in", chatListInfo.id)
-				return
-			}
+			await this._syncChat(chatListInfo.id)
+		}
+	}
+
+	async _syncChat(chatID) {
+		const {messages, receipts} = await this._getMessagesUnsafe(chatID)
+
+		if (messages.length == 0) {
+			this.log("No new messages found in", chatID)
+		} else {
+			this._receiveMessages(chatID, messages, true)
 		}
 
-		if (this.client) {
-			for (const message of messages) {
-				await this.client.sendMessage(message).catch(err =>
-					this.error("Failed to send message", message.id || "with no ID", "to client:", err))
-			}
+		if (receipts.length == 0) {
+			this.log("No new receipts found in", chatID)
 		} else {
-			this.log("No client connected, not sending messages")
+			this._receiveReceiptMulti(chatID, receipts, true)
 		}
 	}
 
@@ -849,7 +1009,15 @@ export default class MessagesPuppeteer {
 	}
 
 	_receiveReceiptDirectLatest(chat_id, receipt_id) {
-		this.log(`Received read receipt ${receipt_id} for chat ${chat_id}`)
+		const receiptMap = this._getReceiptMap(chat_id)
+		const prevReceiptID = (receiptMap.get(1) || 0)
+		if (receipt_id <= prevReceiptID) {
+			this.log(`Received OUTDATED read receipt ${receipt_id} (older than ${prevReceiptID}) for chat ${chat_id}`)
+			return
+		}
+		receiptMap.set(1, receipt_id)
+
+		this.log(`Received read receipt ${receipt_id} (since ${prevReceiptID}) for chat ${chat_id}`)
 		if (this.client) {
 			this.client.sendReceipt({chat_id: chat_id, id: receipt_id})
 				.catch(err => this.error("Error handling read receipt:", err))
@@ -858,8 +1026,26 @@ export default class MessagesPuppeteer {
 		}
 	}
 
-	async _receiveReceiptMulti(chat_id, receipts) {
+	async _receiveReceiptMulti(chat_id, receipts, skipProcessing = false) {
 		// Use async to ensure that receipts are sent in order
+
+		if (!skipProcessing) {
+			const receiptMap = this._getReceiptMap(chat_id)
+			receipts.filter(receipt => {
+				if (receipt.id > (receiptMap.get(receipt.count) || 0)) {
+					receiptMap.set(receipt.count, receipt.id)
+					return true
+				} else {
+					return false
+				}
+			})
+			if (receipts.length == 0) {
+				this.log(`Received ALL OUTDATED bulk read receipts for chat ${chat_id}:`, receipts)
+				return
+			}
+			this._trimReceiptMap(receiptMap)
+		}
+
 		this.log(`Received bulk read receipts for chat ${chat_id}:`, receipts)
 		if (this.client) {
 			for (const receipt of receipts) {