diff --git a/google/cloud/alloydb/connector/refresh.py b/google/cloud/alloydb/connector/refresh.py
index fe0ef483..623a81cc 100644
--- a/google/cloud/alloydb/connector/refresh.py
+++ b/google/cloud/alloydb/connector/refresh.py
@@ -96,7 +96,7 @@ def __init__(
         ca_cert, cert_chain = certs
         # get expiration from client certificate
         cert_obj = x509.load_pem_x509_certificate(cert_chain[0].encode("UTF-8"))
-        self.expiration = cert_obj.not_valid_after.replace(tzinfo=timezone.utc)
+        self.expiration = cert_obj.not_valid_after_utc
 
         # tmpdir and its contents are automatically deleted after the CA cert
         # and cert chain are loaded into the SSLcontext. The values
diff --git a/setup.py b/setup.py
index 324ce593..de7ebba8 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@
 release_status = "Development Status :: 4 - Beta"
 dependencies = [
     "aiohttp",
-    "cryptography>=38.0.3",
+    "cryptography>=42.0.0",
     "requests",
     "google-auth",
     "protobuf",