diff --git a/src/main.rs b/src/main.rs
index 0a21937..035b4ba 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -425,8 +425,8 @@ where
 {
     use serde::Deserialize;
 
-    let opt = Option::<std::borrow::Cow<'de, str>>::deserialize(de)?;
-    match opt.as_deref() {
+    let opt = Option::<&'de str>::deserialize(de)?;
+    match opt {
         None | Some("") => Ok(None),
         Some(s) => s.parse::<T>().map_err(serde::de::Error::custom).map(Some),
     }
@@ -671,48 +671,4 @@ mod parse_query_params {
     )
     "#);
     }
-
-    #[test]
-    fn ipv4_and_empty_ipv6() {
-        let uri = http::Uri::builder()
-            .path_and_query("/update?ipv4=1.2.3.4&ipv6=")
-            .build()
-            .unwrap();
-        let query: Query<FritzBoxUpdateParams> = Query::try_from_uri(&uri).unwrap();
-        insta::assert_debug_snapshot!(query, @r#"
-    Query(
-        FritzBoxUpdateParams {
-            domain: None,
-            ipv4: Some(
-                1.2.3.4,
-            ),
-            ipv6: None,
-            ipv6prefix: None,
-            dualstack: None,
-        },
-    )
-    "#);
-    }
-
-    #[test]
-    fn empty_ipv4_and_ipv6() {
-        let uri = http::Uri::builder()
-            .path_and_query("/update?ipv4=&ipv6=%3A%3A1234")
-            .build()
-            .unwrap();
-        let query: Query<FritzBoxUpdateParams> = Query::try_from_uri(&uri).unwrap();
-        insta::assert_debug_snapshot!(query, @r#"
-    Query(
-        FritzBoxUpdateParams {
-            domain: None,
-            ipv4: None,
-            ipv6: Some(
-                ::1234,
-            ),
-            ipv6prefix: None,
-            dualstack: None,
-        },
-    )
-    "#);
-    }
 }