diff --git a/src/lib.rs b/src/lib.rs
index dda53d42..a84c5c5a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1065,12 +1065,11 @@ impl LightningNode {
     pub fn register_fiat_topup(
         &self,
         email: Option<String>,
-        referral: Option<String>,
         user_iban: String,
         user_currency: String,
     ) -> Result<FiatTopupInfo> {
         self.fiat_topup
-            .register(email, referral, user_iban, user_currency)
+            .register(email, None, user_iban, user_currency)
     }
 
     /// Resets a previous fiat topups registration.
diff --git a/src/lipalightninglib.udl b/src/lipalightninglib.udl
index ccda936c..459ebe76 100644
--- a/src/lipalightninglib.udl
+++ b/src/lipalightninglib.udl
@@ -85,7 +85,7 @@ interface LightningNode {
     TermsAndConditionsStatus get_terms_and_conditions_status(TermsAndConditions terms_and_conditions);
 
     [Throws=LnError]
-    FiatTopupInfo register_fiat_topup(string? email, string? referral_code, string user_iban, string user_currency);
+    FiatTopupInfo register_fiat_topup(string? email, string user_iban, string user_currency);
 
     [Throws=LnError]
     void reset_fiat_topup();