diff --git a/openpgp-card/src/card_app.rs b/openpgp-card/src/card_app.rs
index 8f61c1b..ec0f66f 100644
--- a/openpgp-card/src/card_app.rs
+++ b/openpgp-card/src/card_app.rs
@@ -47,7 +47,7 @@ impl CardApp {
     }
 
     /// Read capabilities from the card, and set them in the CardApp
-    pub fn init_caps(mut self, ard: &Tlv) -> Result<Self> {
+    pub fn init_caps(self, ard: &Tlv) -> Result<Self> {
         // Determine chaining/extended length support from card
         // metadata and cache this information in CardApp (as a
         // CardCaps)