diff --git a/Cargo.lock b/Cargo.lock
index 5ac26f5..7f9c6bd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -185,9 +185,9 @@ checksum = "325918d6fe32f23b19878fe4b34794ae41fc19ddbe53b10571a4874d44ffd39b"
 
 [[package]]
 name = "cc"
-version = "1.2.10"
+version = "1.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13208fcbb66eaeffe09b99fffbe1af420f00a7b35aa99ad683dfc1aa76145229"
+checksum = "e4730490333d58093109dc02c23174c3f4d490998c3fed3cc8e82d57afedb9cf"
 dependencies = [
  "shlex",
 ]
diff --git a/flake-modules/tests.nix b/flake-modules/tests.nix
index 5f0feef..45fc5ff 100644
--- a/flake-modules/tests.nix
+++ b/flake-modules/tests.nix
@@ -237,9 +237,9 @@
                     if IPV4 and IPV6:
                         update_records("127.0.0.1", domain="test", ipv4="1.2.3.4", ipv6="::1234")
                     elif IPV4:
-                        update_records("127.0.0.1", ipv4="1.2.3.4")
+                        update_records("127.0.0.1", ipv4="1.2.3.4", ipv6="")
                     elif IPV6:
-                        update_records("[::1]", ipv6="::1234")
+                        update_records("[::1]",     ipv4="",        ipv6="::1234")
 
                     for domain in DYNAMIC_DOMAINS:
                         if IPV4:
diff --git a/flake.lock b/flake.lock
index 80c565d..5314233 100644
--- a/flake.lock
+++ b/flake.lock
@@ -37,11 +37,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1738021509,
-        "narHash": "sha256-JNUiceGsr7cVBUQxLBF1ILCe99E0qLxsVuet6GsZUuw=",
+        "lastModified": 1738142207,
+        "narHash": "sha256-NGqpVVxNAHwIicXpgaVqJEJWeyqzoQJ9oc8lnK9+WC4=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "9db269672dbdbb519e0bd3ea24f01506c135e46f",
+        "rev": "9d3ae807ebd2981d593cddd0080856873139aa40",
         "type": "github"
       },
       "original": {
diff --git a/src/main.rs b/src/main.rs
index d522390..035b4ba 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -414,6 +414,24 @@ fn main() -> Result<()> {
     .wrap_err("failed to run main loop")
 }
 
+/// Serde deserialization decorator to map empty Strings to None,
+///
+/// Adapted from: <https://github.com/tokio-rs/axum/blob/main/examples/query-params-with-empty-strings/src/main.rs>
+fn empty_string_as_none<'de, D, T>(de: D) -> Result<Option<T>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+    T: std::str::FromStr,
+    T::Err: std::fmt::Display,
+{
+    use serde::Deserialize;
+
+    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),
+    }
+}
+
 #[derive(Debug, serde::Deserialize)]
 #[serde(deny_unknown_fields)]
 struct FritzBoxUpdateParams {
@@ -422,10 +440,10 @@ struct FritzBoxUpdateParams {
     #[serde(default)]
     domain: Option<String>,
     /// IPv4 address for the domain
-    #[serde(default)]
+    #[serde(default, deserialize_with = "empty_string_as_none")]
     ipv4: Option<Ipv4Addr>,
     /// IPv6 address for the domain
-    #[serde(default)]
+    #[serde(default, deserialize_with = "empty_string_as_none")]
     ipv6: Option<Ipv6Addr>,
     /// IPv6 prefix for the home network
     #[allow(unused)]