diff --git a/rpc/errors.go b/rpc/errors.go
index d74b9efc8304e..f32e7725c9da1 100644
--- a/rpc/errors.go
+++ b/rpc/errors.go
@@ -58,10 +58,12 @@ var (
 )
 
 const (
-	errcodeDefault                  = -32000
-	errcodeTimeout                  = -32002
-	errcodePanic                    = -32603
-	errcodeMarshalError             = -32603
+	errcodeDefault      = -32000
+	errcodeTimeout      = -32002
+	errcodePanic        = -32603
+	errcodeMarshalError = -32603
+
+	legacyErrcodeNotificationsUnsupported = -32001
 )
 
 const (
@@ -97,7 +99,11 @@ func (e notificationsUnsupportedError) Is(other error) bool {
 		return true
 	}
 	rpcErr, ok := other.(Error)
-	return ok && rpcErr.ErrorCode() == -32601
+	if ok {
+		code := rpcErr.ErrorCode()
+		return code == -32601 || code == legacyErrcodeNotificationsUnsupported
+	}
+	return false
 }
 
 type subscriptionNotFoundError struct{ namespace, subscription string }