diff --git a/plugins/qca-pkcs11/qca-pkcs11.cpp b/plugins/qca-pkcs11/qca-pkcs11.cpp
index 97451a73..103a34c8 100644
--- a/plugins/qca-pkcs11/qca-pkcs11.cpp
+++ b/plugins/qca-pkcs11/qca-pkcs11.cpp
@@ -2264,7 +2264,7 @@ pkcs11KeyStoreListContext::serializeCertificateId (
 	buf.resize ((int)len);
 
 	serialized = QString ().sprintf (
-		"qca-pkcs11/%s/%d/",
+		"qca-pkcs11/0/%s/%d/",
 		myPrintable(escapeString (QString::fromUtf8 (buf))),
 		has_private ? 1 : 0
 	);
@@ -2328,6 +2328,10 @@ pkcs11KeyStoreListContext::deserializeCertificateId (
 			throw pkcs11Exception (CKR_FUNCTION_FAILED, "Invalid serialization");
 		}
 
+		if (list[n++].toInt () != 0) {
+			throw pkcs11Exception (CKR_FUNCTION_FAILED, "Invalid serialization version");
+		}
+
 		if (
 			(rv = pkcs11h_certificate_deserializeCertificateId (
 				&certificate_id,