diff --git a/libwvdrmengine/oemcrypto/include/OEMCryptoCENC.h b/libwvdrmengine/oemcrypto/include/OEMCryptoCENC.h
index 4b26675d..f34c4272 100644
--- a/libwvdrmengine/oemcrypto/include/OEMCryptoCENC.h
+++ b/libwvdrmengine/oemcrypto/include/OEMCryptoCENC.h
@@ -4682,6 +4682,9 @@ OEMCryptoResult OEMCrypto_UpdateUsageEntry(
  * already InactiveUsed or InactiveUnused, then this function does not change
  * the entry or its state.
  *
+ * This API is deprecated in OEMCrypto v19, but will not be removed until
+ * OEMCrypto v22 to maintain backwards compatibility.
+ *
  * @param[in] session: handle for the session to be used.
  * @param[in] pst: pointer to memory containing Provider Session Token.
  * @param[in] pst_length: length of the pst, in bytes.
@@ -4777,6 +4780,9 @@ OEMCryptoResult OEMCrypto_DeactivateUsageEntry(OEMCrypto_SESSION session,
  * Devices that do not implement a Session Usage Table may return
  * OEMCrypto_ERROR_NOT_IMPLEMENTED.
  *
+ * This API is deprecated in OEMCrypto v19, but will not be removed until
+ * OEMCrypto v22 to maintain backwards compatibility.
+ *
  * @param[in] session: handle for the session to be used.
  * @param[in] pst: pointer to memory containing Provider Session Token.
  * @param[in] pst_length: length of the pst, in bytes.