diff --git a/mmtk/Cargo.lock b/mmtk/Cargo.lock
index 3442794..cf8e713 100644
--- a/mmtk/Cargo.lock
+++ b/mmtk/Cargo.lock
@@ -424,7 +424,7 @@ dependencies = [
 [[package]]
 name = "mmtk"
 version = "0.24.0"
-source = "git+https://github.com/mmtk/mmtk-core.git?rev=d291cda52790a34ed10bf72b4c5e27c3ab89a242#d291cda52790a34ed10bf72b4c5e27c3ab89a242"
+source = "git+https://github.com/mmtk/mmtk-core.git?rev=20e56c25713fc42ec6747f9a38d9c7f4fa820f12#20e56c25713fc42ec6747f9a38d9c7f4fa820f12"
 dependencies = [
  "atomic",
  "atomic-traits",
@@ -459,7 +459,7 @@ dependencies = [
 [[package]]
 name = "mmtk-macros"
 version = "0.24.0"
-source = "git+https://github.com/mmtk/mmtk-core.git?rev=d291cda52790a34ed10bf72b4c5e27c3ab89a242#d291cda52790a34ed10bf72b4c5e27c3ab89a242"
+source = "git+https://github.com/mmtk/mmtk-core.git?rev=20e56c25713fc42ec6747f9a38d9c7f4fa820f12#20e56c25713fc42ec6747f9a38d9c7f4fa820f12"
 dependencies = [
  "proc-macro-error",
  "proc-macro2",
@@ -565,9 +565,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.80"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a56dea16b0a29e94408b9aa5e2940a4eedbd128a1ba20e8f7ae60fd3d465af0e"
+checksum = "3d1597b0c024618f09a9c3b8655b7e430397a36d23fdafec26d6965e9eec3eba"
 dependencies = [
  "unicode-ident",
 ]
diff --git a/mmtk/Cargo.toml b/mmtk/Cargo.toml
index 93009c2..9cdd45e 100644
--- a/mmtk/Cargo.toml
+++ b/mmtk/Cargo.toml
@@ -37,7 +37,7 @@ features = ["is_mmtk_object", "object_pinning"]
 
 # Uncomment the following lines to use mmtk-core from the official repository.
 git = "https://github.com/mmtk/mmtk-core.git"
-rev = "d291cda52790a34ed10bf72b4c5e27c3ab89a242"
+rev = "20e56c25713fc42ec6747f9a38d9c7f4fa820f12"
 
 # Uncomment the following line to use mmtk-core from a local repository.
 #path = "../../mmtk-core"
diff --git a/mmtk/src/api.rs b/mmtk/src/api.rs
index 1e58651..0a8303b 100644
--- a/mmtk/src/api.rs
+++ b/mmtk/src/api.rs
@@ -148,7 +148,7 @@ pub extern "C" fn mmtk_post_alloc(
 
 #[no_mangle]
 pub extern "C" fn mmtk_will_never_move(object: ObjectReference) -> bool {
-    !object.is_movable()
+    !object.is_movable::<Ruby>()
 }
 
 #[no_mangle]
@@ -199,18 +199,18 @@ pub extern "C" fn mmtk_total_bytes() -> usize {
 
 #[no_mangle]
 pub extern "C" fn mmtk_is_reachable(object: ObjectReference) -> bool {
-    object.is_reachable()
+    object.is_reachable::<Ruby>()
 }
 
 #[no_mangle]
 pub extern "C" fn mmtk_is_live_object(object: ObjectReference) -> bool {
-    memory_manager::is_live_object(object)
+    memory_manager::is_live_object::<Ruby>(object)
 }
 
 #[no_mangle]
 pub extern "C" fn mmtk_get_forwarded_object(object: ObjectReference) -> ObjectReference {
     object
-        .get_forwarded_object()
+        .get_forwarded_object::<Ruby>()
         .unwrap_or(ObjectReference::NULL)
 }
 
diff --git a/mmtk/src/ppp.rs b/mmtk/src/ppp.rs
index e1542c8..f815878 100644
--- a/mmtk/src/ppp.rs
+++ b/mmtk/src/ppp.rs
@@ -70,8 +70,8 @@ impl PPPRegistry {
 
             probe!(mmtk_ruby, remove_dead_ppps_start, ppps.len());
             ppps.retain_mut(|obj| {
-                if obj.is_live() {
-                    *obj = obj.get_forwarded_object().unwrap_or(*obj);
+                if obj.is_live::<Ruby>() {
+                    *obj = obj.get_forwarded_object::<Ruby>().unwrap_or(*obj);
                     true
                 } else {
                     log::trace!("  PPP removed: {}", *obj);
diff --git a/mmtk/src/weak_proc.rs b/mmtk/src/weak_proc.rs
index 088a0a2..a431521 100644
--- a/mmtk/src/weak_proc.rs
+++ b/mmtk/src/weak_proc.rs
@@ -122,7 +122,7 @@ impl GCWork<Ruby> for ProcessObjFreeCandidates {
         let mut new_candidates = Vec::new();
 
         for object in obj_free_candidates.iter().copied() {
-            if object.is_reachable() {
+            if object.is_reachable::<Ruby>() {
                 // Forward and add back to the candidate list.
                 let new_object = object.forward();
                 trace!(
@@ -216,6 +216,6 @@ trait Forwardable {
 
 impl Forwardable for ObjectReference {
     fn forward(&self) -> Self {
-        self.get_forwarded_object().unwrap_or(*self)
+        self.get_forwarded_object::<Ruby>().unwrap_or(*self)
     }
 }