diff --git a/ruma-common/src/thirdparty.rs b/ruma-common/src/thirdparty.rs
index 21eabcf1..258d242b 100644
--- a/ruma-common/src/thirdparty.rs
+++ b/ruma-common/src/thirdparty.rs
@@ -23,13 +23,12 @@ pub struct Protocol {
     pub location_fields: Vec<String>,
 
     /// A content URI representing an icon for the third party protocol.
-    #[cfg(not(feature = "unstable-synapse-quirks"))]
+    ///
+    /// If you activate the `unstable-synapse-quirks` feature, this field being absent in JSON will
+    /// give you an empty string here.
+    #[cfg_attr(feature = "unstable-synapse-quirks", serde(default))]
     pub icon: String,
 
-    /// A content URI representing an icon for the third party protocol.
-    #[cfg(feature = "unstable-synapse-quirks")]
-    pub icon: Option<String>,
-
     /// The type definitions for the fields defined in `user_fields` and `location_fields`.
     pub field_types: BTreeMap<String, FieldType>,
 
@@ -50,13 +49,8 @@ pub struct ProtocolInit {
     pub location_fields: Vec<String>,
 
     /// A content URI representing an icon for the third party protocol.
-    #[cfg(not(feature = "unstable-synapse-quirks"))]
     pub icon: String,
 
-    /// A content URI representing an icon for the third party protocol.
-    #[cfg(feature = "unstable-synapse-quirks")]
-    pub icon: Option<String>,
-
     /// The type definitions for the fields defined in `user_fields` and `location_fields`.
     pub field_types: BTreeMap<String, FieldType>,