diff --git a/mautrix_telegram/portal_util/sponsored_message.py b/mautrix_telegram/portal_util/sponsored_message.py
index 7db458de..ec6ca286 100644
--- a/mautrix_telegram/portal_util/sponsored_message.py
+++ b/mautrix_telegram/portal_util/sponsored_message.py
@@ -20,6 +20,7 @@ import html
 
 from telethon.tl.functions.channels import GetSponsoredMessagesRequest
 from telethon.tl.types import Channel, InputChannel, PeerChannel, PeerUser, SponsoredMessage, User
+from telethon.tl.types.messages import SponsoredMessages, SponsoredMessagesEmpty
 
 from mautrix.types import MessageType, TextMessageEventContent
 
@@ -32,8 +33,9 @@ async def get_sponsored_message(
     entity: InputChannel,
 ) -> tuple[SponsoredMessage | None, int | None, Channel | User | None]:
     resp = await user.client(GetSponsoredMessagesRequest(entity))
-    if len(resp.messages) == 0:
+    if isinstance(resp, SponsoredMessagesEmpty):
         return None, None, None
+    assert isinstance(resp, SponsoredMessages)
     msg = resp.messages[0]
     if isinstance(msg.from_id, PeerUser):
         entities = resp.users
diff --git a/requirements.txt b/requirements.txt
index 45d22468..36efcec8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,8 +4,8 @@ commonmark>=0.8,<0.10
 aiohttp>=3,<4
 yarl>=1,<2
 mautrix>=0.18.6,<0.19
-#telethon>=1.24,<1.25
-tulir-telethon==1.26.0a8
+#telethon>=1.25.4,<1.26
+tulir-telethon==1.26.0a10
 asyncpg>=0.20,<0.27
 mako>=1,<2
 setuptools