diff --git a/crates/header-translator/src/stmt.rs b/crates/header-translator/src/stmt.rs
index 7e79d700f..ff06650d3 100644
--- a/crates/header-translator/src/stmt.rs
+++ b/crates/header-translator/src/stmt.rs
@@ -306,7 +306,7 @@ pub enum Mutability {
     MutableWithImmutableSuperclass(ItemIdentifier),
     #[default]
     InteriorMutable,
-    // MainThreadOnly,
+    MainThreadOnly,
 }
 
 impl Mutability {
@@ -330,6 +330,7 @@ impl fmt::Display for Mutability {
                 write!(f, "MutableWithImmutableSuperclass<{}>", superclass.path())
             }
             Self::InteriorMutable => write!(f, "InteriorMutable"),
+            Self::MainThreadOnly => write!(f, "MainThreadOnly"),
         }
     }
 }
@@ -349,7 +350,6 @@ pub enum Stmt {
         mutability: Mutability,
         skipped: bool,
         sendable: bool,
-        mainthreadonly: bool,
     },
     /// @interface class_name (name) <protocols*>
     /// ->
@@ -565,7 +565,7 @@ impl Stmt {
                     context,
                 );
 
-                let (sendable, mainthreadonly) = parse_attributes(entity, context);
+                let (sendable, mut mainthreadonly) = parse_attributes(entity, context);
 
                 let mut protocols = Default::default();
                 parse_protocols(entity, &mut protocols, context);
@@ -579,7 +579,17 @@ impl Stmt {
 
                 let superclasses: Vec<_> = superclasses_full
                     .iter()
-                    .map(|(id, generics, _)| (id.clone(), generics.clone()))
+                    .map(|(id, generics, entity)| {
+                        // Ignore sendability on superclasses; because it's an auto trait, it's propagated to subclasses anyhow!
+                        let (_sendable, superclass_mainthreadonly) =
+                            parse_attributes(entity, context);
+
+                        if superclass_mainthreadonly {
+                            mainthreadonly = true;
+                        }
+
+                        (id.clone(), generics.clone())
+                    })
                     .collect();
 
                 // Used for duplicate checking (sometimes the subclass
@@ -592,8 +602,6 @@ impl Stmt {
                     .filter_map(|(superclass_id, _, entity)| {
                         let superclass_data = context.class_data.get(&superclass_id.name);
 
-                        // let (sendable, mainthreadonly) = parse_attributes(entity, context);
-
                         // Explicitly keep going, even if the class itself is skipped
                         // if superclass_data.skipped
 
@@ -647,10 +655,13 @@ impl Stmt {
                     superclasses,
                     designated_initializers,
                     derives: data.map(|data| data.derives.clone()).unwrap_or_default(),
-                    mutability: data.map(|data| data.mutability.clone()).unwrap_or_default(),
+                    mutability: if mainthreadonly {
+                        Mutability::MainThreadOnly
+                    } else {
+                        data.map(|data| data.mutability.clone()).unwrap_or_default()
+                    },
                     skipped: data.map(|data| data.definition_skipped).unwrap_or_default(),
                     sendable: sendable.unwrap_or(false),
-                    mainthreadonly,
                 })
                 .chain(protocols.into_iter().map(|protocol| Self::ProtocolImpl {
                     cls: id.clone(),
@@ -694,7 +705,7 @@ impl Stmt {
                 );
 
                 let (sendable, mainthreadonly) = parse_attributes(entity, context);
-                if sendable.is_some() {
+                if let Some(sendable) = sendable {
                     error!(?sendable, "sendable on category");
                 }
                 if mainthreadonly {
@@ -710,7 +721,18 @@ impl Stmt {
 
                 let superclasses: Vec<_> = parse_superclasses(entity, context)
                     .into_iter()
-                    .map(|(id, generics, _)| (id, generics))
+                    .map(|(id, generics, entity)| {
+                        let (sendable, mainthreadonly) = parse_attributes(&entity, context);
+
+                        if let Some(sendable) = sendable {
+                            error!(?sendable, "sendable on category superclass");
+                        }
+                        if mainthreadonly {
+                            error!("@UIActor on category superclass");
+                        }
+
+                        (id, generics)
+                    })
                     .collect();
 
                 let subclass_methods = if let Mutability::ImmutableWithMutableSubclass(subclass) =
@@ -719,8 +741,6 @@ impl Stmt {
                     let subclass_data = context.class_data.get(&subclass.name);
                     assert!(!subclass_data.map(|data| data.skipped).unwrap_or_default());
 
-                    // let (sendable, mainthreadonly) = parse_attributes(entity, context);
-
                     let (mut methods, _) = parse_methods(
                         entity,
                         |name| {
@@ -1320,7 +1340,6 @@ impl fmt::Display for Stmt {
                 mutability,
                 skipped,
                 sendable,
-                mainthreadonly: _,
             } => {
                 if *skipped {
                     return Ok(());
@@ -1337,7 +1356,8 @@ impl fmt::Display for Stmt {
                     Mutability::Immutable
                     | Mutability::Mutable
                     | Mutability::ImmutableWithMutableSubclass(_)
-                    | Mutability::InteriorMutable => id.feature(),
+                    | Mutability::InteriorMutable
+                    | Mutability::MainThreadOnly => id.feature(),
                 };
 
                 let (superclass, superclasses_rest) = superclasses.split_at(1);
diff --git a/crates/icrate/examples/delegate.rs b/crates/icrate/examples/delegate.rs
index 6f3bef426..5615e7f13 100644
--- a/crates/icrate/examples/delegate.rs
+++ b/crates/icrate/examples/delegate.rs
@@ -24,9 +24,8 @@ declare_class!(
     mod ivars;
 
     unsafe impl ClassType for AppDelegate {
-        #[inherits(NSObject)]
-        type Super = icrate::AppKit::NSResponder;
-        type Mutability = mutability::InteriorMutable;
+        type Super = NSObject;
+        type Mutability = mutability::MainThreadOnly;
         const NAME: &'static str = "MyAppDelegate";
     }
 
diff --git a/crates/icrate/src/common.rs b/crates/icrate/src/common.rs
index fdc9fdaae..b6ba9c38f 100644
--- a/crates/icrate/src/common.rs
+++ b/crates/icrate/src/common.rs
@@ -14,8 +14,8 @@ pub(crate) use std::os::raw::{
 pub(crate) use objc2::ffi::{NSInteger, NSIntegerMax, NSUInteger, NSUIntegerMax, IMP};
 #[cfg(feature = "objective-c")]
 pub(crate) use objc2::mutability::{
-    Immutable, ImmutableWithMutableSubclass, InteriorMutable, IsIdCloneable, Mutable,
-    MutableWithImmutableSuperclass,
+    Immutable, ImmutableWithMutableSubclass, InteriorMutable, IsIdCloneable, MainThreadOnly,
+    Mutable, MutableWithImmutableSuperclass,
 };
 #[cfg(feature = "objective-c")]
 pub(crate) use objc2::rc::{Allocated, DefaultId, Id};
diff --git a/crates/icrate/src/fixes/AppKit/mod.rs b/crates/icrate/src/fixes/AppKit/mod.rs
index a4c965482..44975eff4 100644
--- a/crates/icrate/src/fixes/AppKit/mod.rs
+++ b/crates/icrate/src/fixes/AppKit/mod.rs
@@ -36,7 +36,7 @@ extern_class!(
     unsafe impl ClassType for NSPopover {
         #[inherits(NSObject)]
         type Super = crate::AppKit::NSResponder;
-        type Mutability = InteriorMutable;
+        type Mutability = MainThreadOnly;
     }
 );
 
diff --git a/crates/icrate/src/fixes/AuthenticationServices/mod.rs b/crates/icrate/src/fixes/AuthenticationServices/mod.rs
index 3de214181..26657c8f6 100644
--- a/crates/icrate/src/fixes/AuthenticationServices/mod.rs
+++ b/crates/icrate/src/fixes/AuthenticationServices/mod.rs
@@ -19,7 +19,7 @@ extern_class!(
     #[cfg(feature = "AuthenticationServices_ASCredentialProviderViewController")]
     unsafe impl ClassType for ASCredentialProviderViewController {
         type Super = ASViewController;
-        type Mutability = InteriorMutable;
+        type Mutability = MainThreadOnly;
     }
 );
 
@@ -31,7 +31,7 @@ extern_class!(
     #[cfg(feature = "AuthenticationServices_ASAccountAuthenticationModificationViewController")]
     unsafe impl ClassType for ASAccountAuthenticationModificationViewController {
         type Super = ASViewController;
-        type Mutability = InteriorMutable;
+        type Mutability = MainThreadOnly;
     }
 );
 
@@ -43,6 +43,6 @@ extern_class!(
     #[cfg(feature = "AuthenticationServices_ASAuthorizationAppleIDButton")]
     unsafe impl ClassType for ASAuthorizationAppleIDButton {
         type Super = ASControl;
-        type Mutability = InteriorMutable;
+        type Mutability = MainThreadOnly;
     }
 );
diff --git a/crates/icrate/src/generated b/crates/icrate/src/generated
index bfe4ba4a9..7205d0e7b 160000
--- a/crates/icrate/src/generated
+++ b/crates/icrate/src/generated
@@ -1 +1 @@
-Subproject commit bfe4ba4a9871a46d1f9374854501b0a32eb608a6
+Subproject commit 7205d0e7bd68d94c0b6a4effddc7b746df7eae52