diff --git a/downstream.go b/downstream.go
index 4b9f72e..51d3115 100644
--- a/downstream.go
+++ b/downstream.go
@@ -752,7 +752,7 @@ func (dc *downstreamConn) handleMessageUnregistered(ctx context.Context, msg *ir
 
 		dc.SendMessage(ctx, generateAwayReply(dc.away != nil))
 	default:
-		dc.logger.Printf("unhandled message: %v", msg)
+		dc.logger.Debugf("unhandled message: %v", msg)
 		return newUnknownCommandError(msg.Command)
 	}
 	return nil
@@ -3318,7 +3318,7 @@ func (dc *downstreamConn) handleMessageRegistered(ctx context.Context, msg *irc.
 			}}
 		}
 	default:
-		dc.logger.Printf("unhandled message: %v", msg)
+		dc.logger.Debugf("unhandled message: %v", msg)
 
 		// Only forward unknown commands in single-upstream mode
 		if dc.network == nil {
diff --git a/upstream.go b/upstream.go
index 979bb60..80f0517 100644
--- a/upstream.go
+++ b/upstream.go
@@ -763,7 +763,7 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 				})
 			}
 		default:
-			uc.logger.Printf("unhandled message: %v", msg)
+			uc.logger.Debugf("unhandled message: %v", msg)
 		}
 	case "AUTHENTICATE":
 		if uc.saslClient == nil {
@@ -1819,7 +1819,7 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 		}
 		uc.forwardMsgByID(ctx, downstreamID, msg)
 	default:
-		uc.logger.Printf("unhandled message: %v", msg)
+		uc.logger.Debugf("unhandled message: %v", msg)
 		uc.forwardMsgByID(ctx, downstreamID, msg)
 	}
 	return nil