Index: src/runtime/ObjFW_RT.h
==================================================================
--- src/runtime/ObjFW_RT.h
+++ src/runtime/ObjFW_RT.h
@@ -309,13 +309,13 @@
     SEL _Nonnull sel);
 extern IMP _Nonnull objc_msg_lookup_super(struct objc_super *_Nonnull super,
     SEL _Nonnull sel);
 extern IMP _Nonnull objc_msg_lookup_super_stret(
     struct objc_super *_Nonnull super, SEL _Nonnull sel);
-extern id _Nullable objc_lookUpClass(const char *_Nonnull name);
-extern id _Nullable objc_getClass(const char *_Nonnull name);
-extern id _Nonnull objc_getRequiredClass(const char *_Nonnull name);
+extern Class _Nullable objc_lookUpClass(const char *_Nonnull name);
+extern Class _Nullable objc_getClass(const char *_Nonnull name);
+extern Class _Nonnull objc_getRequiredClass(const char *_Nonnull name);
 extern Class _Nullable objc_lookup_class(const char *_Nonnull name);
 extern Class _Nonnull objc_get_class(const char *_Nonnull name);
 extern void objc_exception_throw(id _Nullable object);
 extern int objc_sync_enter(id _Nullable object);
 extern int objc_sync_exit(id _Nullable object);

Index: src/runtime/ObjFW_RT.sfd
==================================================================
--- src/runtime/ObjFW_RT.sfd
+++ src/runtime/ObjFW_RT.sfd
@@ -9,13 +9,13 @@
 void glue___objc_exec_class(void *_Nonnull module)(a0)
 IMP _Nonnull glue_objc_msg_lookup(id _Nullable obj, SEL _Nonnull sel)(a0,a1)
 IMP _Nonnull glue_objc_msg_lookup_stret(id _Nullable obj, SEL _Nonnull sel)(a0,a1)
 IMP _Nonnull glue_objc_msg_lookup_super(struct objc_super *_Nonnull super, SEL _Nonnull sel)(a0,a1)
 IMP _Nonnull glue_objc_msg_lookup_super_stret(struct objc_super *_Nonnull super, SEL _Nonnull sel)(a0,a1)
-id _Nullable glue_objc_lookUpClass(const char *_Nonnull name)(a0)
-id _Nullable glue_objc_getClass(const char *_Nonnull name)(a0)
-id _Nonnull glue_objc_getRequiredClass(const char *_Nonnull name)(a0)
+Class _Nullable glue_objc_lookUpClass(const char *_Nonnull name)(a0)
+Class _Nullable glue_objc_getClass(const char *_Nonnull name)(a0)
+Class _Nonnull glue_objc_getRequiredClass(const char *_Nonnull name)(a0)
 Class _Nullable glue_objc_lookup_class(const char *_Nonnull name)(a0)
 Class _Nonnull glue_objc_get_class(const char *_Nonnull name)(a0)
 void glue_objc_exception_throw(id _Nonnull object)(a0)
 int glue_objc_sync_enter(id _Nullable object)(a0)
 int glue_objc_sync_exit(id _Nullable object)(a0)

Index: src/runtime/amiga-glue.m
==================================================================
--- src/runtime/amiga-glue.m
+++ src/runtime/amiga-glue.m
@@ -52,23 +52,23 @@
     SEL sel OBJC_M68K_REG("a1"))
 {
 	return objc_msg_lookup_super_stret(super, sel);
 }
 
-id
+Class
 glue_objc_lookUpClass(const char *name OBJC_M68K_REG("a0"))
 {
 	return objc_lookUpClass(name);
 }
 
-id
+Class
 glue_objc_getClass(const char *name OBJC_M68K_REG("a0"))
 {
 	return objc_getClass(name);
 }
 
-id
+Class
 glue_objc_getRequiredClass(const char *name OBJC_M68K_REG("a0"))
 {
 	return objc_getRequiredClass(name);
 }
 

Index: src/runtime/class.m
==================================================================
--- src/runtime/class.m
+++ src/runtime/class.m
@@ -475,11 +475,11 @@
 	process_load_queue();
 
 	objc_global_mutex_unlock();
 }
 
-id
+Class
 objc_lookUpClass(const char *name)
 {
 	Class cls;
 
 	if ((cls = objc_classname_to_class(name, true)) == NULL)
@@ -498,17 +498,17 @@
 		return Nil;
 
 	return cls;
 }
 
-id
+Class
 objc_getClass(const char *name)
 {
 	return objc_lookUpClass(name);
 }
 
-id
+Class
 objc_getRequiredClass(const char *name)
 {
 	Class cls;
 
 	if ((cls = objc_getClass(name)) == Nil)

Index: src/runtime/linklib/linklib.m
==================================================================
--- src/runtime/linklib/linklib.m
+++ src/runtime/linklib/linklib.m
@@ -125,23 +125,23 @@
 objc_msg_lookup_super_stret(struct objc_super *super, SEL sel)
 {
 	return glue_objc_msg_lookup_super_stret(super, sel);
 }
 
-id
+Class
 objc_lookUpClass(const char *name)
 {
 	return glue_objc_lookUpClass(name);
 }
 
-id
+Class
 objc_getClass(const char *name)
 {
 	return glue_objc_getClass(name);
 }
 
-id
+Class
 objc_getRequiredClass(const char *name)
 {
 	return glue_objc_getRequiredClass(name);
 }
 

Index: src/runtime/private.h
==================================================================
--- src/runtime/private.h
+++ src/runtime/private.h
@@ -177,15 +177,15 @@
     struct objc_super *_Nonnull super OBJC_M68K_REG("a0"),
     SEL _Nonnull sel OBJC_M68K_REG("a1"));
 extern IMP _Nonnull glue_objc_msg_lookup_super_stret(
     struct objc_super *_Nonnull super OBJC_M68K_REG("a0"),
     SEL _Nonnull sel OBJC_M68K_REG("a1"));
-extern id _Nullable glue_objc_lookUpClass(
+extern Class _Nullable glue_objc_lookUpClass(
     const char *_Nonnull name OBJC_M68K_REG("a0"));
-extern id _Nullable glue_objc_getClass(
+extern Class _Nullable glue_objc_getClass(
     const char *_Nonnull name OBJC_M68K_REG("a0"));
-extern id _Nonnull glue_objc_getRequiredClass(
+extern Class _Nonnull glue_objc_getRequiredClass(
     const char *_Nonnull name OBJC_M68K_REG("a0"));
 extern Class _Nullable glue_objc_lookup_class(
     const char *_Nonnull name OBJC_M68K_REG("a0"));
 extern Class _Nonnull glue_objc_get_class(
     const char *_Nonnull name OBJC_M68K_REG("a0"));