diff --git a/ios/components/RNAddToWalletButtonView.swift b/ios/components/RNAddToWalletButtonView.swift
index 09e8ccf..0c735d0 100644
--- a/ios/components/RNAddToWalletButtonView.swift
+++ b/ios/components/RNAddToWalletButtonView.swift
@@ -57,7 +57,8 @@ class RNAddToWalletButtonView: UIView {
   }
   
   private func updateButtonStyle() {
-    let style: PKAddPassButtonStyle = (buttonStyle.lowercased == "black") ? .black : .blackOutline
+    let styleString = (buttonStyle as String).lowercased()
+    let style: PKAddPassButtonStyle = (styleString == "black") ? .black : .blackOutline
     addPassButton.removeFromSuperview()
     addPassButton = PKAddPassButton(addPassButtonStyle: style)