diff --git a/example/wvpl_cas_proxy_environment_example b/example/wvpl_cas_proxy_environment_example
index a8a898c..946fce4 100644
Binary files a/example/wvpl_cas_proxy_environment_example and b/example/wvpl_cas_proxy_environment_example differ
diff --git a/example/wvpl_cas_proxy_session_example b/example/wvpl_cas_proxy_session_example
index 874b42e..41d6545 100644
Binary files a/example/wvpl_cas_proxy_session_example and b/example/wvpl_cas_proxy_session_example differ
diff --git a/libwvpl_cas_proxy.so b/libwvpl_cas_proxy.so
index d53e266..762cc87 100755
Binary files a/libwvpl_cas_proxy.so and b/libwvpl_cas_proxy.so differ
diff --git a/media_cas_proxy_sdk/external/common/wvpl/wvpl_cas_proxy_session.h b/media_cas_proxy_sdk/external/common/wvpl/wvpl_cas_proxy_session.h
index f4d6f90..0541db4 100644
--- a/media_cas_proxy_sdk/external/common/wvpl/wvpl_cas_proxy_session.h
+++ b/media_cas_proxy_sdk/external/common/wvpl/wvpl_cas_proxy_session.h
@@ -13,7 +13,6 @@
 #include <string>
 #include <vector>
 
-#include "absl/synchronization/mutex.h"
 #include "sdk/external/common/wvpl/wvpl_sdk_session.h"
 
 namespace widevine {
@@ -107,9 +106,6 @@ class WvPLCASProxySession : public WvPLSDKSession {
 
   // holds all the WvPLCasKey objects.  Used when generating a CAS License.
   std::vector<WvPLCasKey> cas_keys_;
-
-  // Mutex to protect the keys, |cas_keys_|, owned by this session.
-  mutable std::unique_ptr<absl::Mutex> cas_keys_mutex_;
 };
 
 }  // namespace wv_pl_sdk
diff --git a/sdk/external/common/wvpl/wvpl_sdk_environment.h b/sdk/external/common/wvpl/wvpl_sdk_environment.h
index 943345f..4af2a9c 100644
--- a/sdk/external/common/wvpl/wvpl_sdk_environment.h
+++ b/sdk/external/common/wvpl/wvpl_sdk_environment.h
@@ -13,7 +13,6 @@
 #include <string>
 
 #include "sdk/external/common/wvpl/wvpl_types.h"
-#include "protos/public/drm_certificate.pb.h"
 
 namespace widevine {
 class DeviceCertificateStatusList;
@@ -111,8 +110,7 @@ class WvPLSDKEnvironment {
 
  private:
   // Get the expected service type for drm service certificate.
-  virtual widevine::DrmCertificate::ServiceType
-  GetExpectedServiceCertificateType();
+  virtual int GetExpectedServiceCertificateType();
 
   // Check the type of |service_certificate|. Returns "OK" if the cert can be
   // used for the current SDK, else an error status.