diff --git a/Cargo.toml b/Cargo.toml
index c0797e7..ce406ad 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,11 +13,11 @@ documentation = "https://docs.rs/crate/pythonize/"
 
 [dependencies]
 serde = { version = "1.0", default-features = false, features = ["std"] }
-pyo3 = { version = "0.26", default-features = false }
+pyo3 = { version = "0.27", default-features = false }
 
 [dev-dependencies]
 serde = { version = "1.0", default-features = false, features = ["derive"] }
-pyo3 = { version = "0.26", default-features = false, features = ["auto-initialize", "macros", "py-clone"] }
+pyo3 = { version = "0.27", default-features = false, features = ["auto-initialize", "macros", "py-clone"] }
 serde_json = "1.0"
 serde_bytes = "0.11"
 maplit = "1.0.2"
diff --git a/src/error.rs b/src/error.rs
index 7828a71..b608106 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -1,5 +1,5 @@
 use pyo3::PyErr;
-use pyo3::{exceptions::*, DowncastError, DowncastIntoError};
+use pyo3::{exceptions::*, CastError, CastIntoError};
 use serde::{de, ser};
 use std::convert::Infallible;
 use std::error;
@@ -153,18 +153,18 @@ impl From<PyErr> for PythonizeError {
     }
 }
 
-/// Handle errors that occur when attempting to use `PyAny::cast_as`
-impl<'a, 'py> From<DowncastError<'a, 'py>> for PythonizeError {
-    fn from(other: DowncastError<'a, 'py>) -> Self {
+/// Handle errors that occur when attempting to use `PyAny::cast`
+impl<'a, 'py> From<CastError<'a, 'py>> for PythonizeError {
+    fn from(other: CastError<'a, 'py>) -> Self {
         Self {
             inner: Box::new(ErrorImpl::UnexpectedType(other.to_string())),
         }
     }
 }
 
-/// Handle errors that occur when attempting to use `PyAny::cast_as`
-impl<'py> From<DowncastIntoError<'py>> for PythonizeError {
-    fn from(other: DowncastIntoError<'py>) -> Self {
+/// Handle errors that occur when attempting to use `PyAny::cast`
+impl<'py> From<CastIntoError<'py>> for PythonizeError {
+    fn from(other: CastIntoError<'py>) -> Self {
         Self {
             inner: Box::new(ErrorImpl::UnexpectedType(other.to_string())),
         }
diff --git a/tests/test_with_serde_path_to_err.rs b/tests/test_with_serde_path_to_err.rs
index d92c4d1..82fd8bb 100644
--- a/tests/test_with_serde_path_to_err.rs
+++ b/tests/test_with_serde_path_to_err.rs
@@ -100,7 +100,10 @@ fn test_de_invalid() {
         let err = serde_path_to_error::deserialize::<_, Root<String>>(de).unwrap_err();
 
         assert_eq!(err.path().to_string(), "root_map.nested_1.nested_key");
-        assert_eq!(err.to_string(), "root_map.nested_1.nested_key: unexpected type: 'int' object cannot be converted to 'PyString'");
+        assert_eq!(
+            err.to_string(),
+            "root_map.nested_1.nested_key: unexpected type: 'int' object cannot be cast as 'str'"
+        );
     })
 }
 
@@ -143,7 +146,7 @@ fn test_ser_valid() {
             .get_item("root_map")
             .unwrap()
             .unwrap()
-            .downcast_into::<PyDict>()
+            .cast_into::<PyDict>()
             .unwrap();
         assert_eq!(root_map.len(), 2);
 
@@ -151,7 +154,7 @@ fn test_ser_valid() {
             .get_item("nested_0")
             .unwrap()
             .unwrap()
-            .downcast_into::<PyDict>()
+            .cast_into::<PyDict>()
             .unwrap();
         assert_eq!(nested_0.len(), 1);
         let nested_key_0: String = nested_0
@@ -166,7 +169,7 @@ fn test_ser_valid() {
             .get_item("nested_1")
             .unwrap()
             .unwrap()
-            .downcast_into::<PyDict>()
+            .cast_into::<PyDict>()
             .unwrap();
         assert_eq!(nested_1.len(), 1);
         let nested_key_1: String = nested_1