diff --git a/libp2p/muxers/mplex/coder.nim b/libp2p/muxers/mplex/coder.nim
index 891e535..a0a2401 100644
--- a/libp2p/muxers/mplex/coder.nim
+++ b/libp2p/muxers/mplex/coder.nim
@@ -26,7 +26,7 @@ type
     msgType: MessageType
     data: seq[byte]
 
-proc readMplexVarint(conn: Connection): Future[uint] {.async, gcsafe.} =
+proc readMplexVarint(conn: Connection): Future[uint64] {.async, gcsafe.} =
   var
     varint: uint
     length: int