diff --git a/include/QtCrypto/qca_core.h b/include/QtCrypto/qca_core.h
index 39d6c89e..3977171c 100644
--- a/include/QtCrypto/qca_core.h
+++ b/include/QtCrypto/qca_core.h
@@ -431,6 +431,7 @@ namespace QCA
 				l->logBinaryMessage (blob, s); \
 			} \
 		} while (false)
+
 	/**
 	   Test if QCA can access the root CA certificates
 
diff --git a/include/QtCrypto/qcaprovider.h b/include/QtCrypto/qcaprovider.h
index a2ee503f..f564657e 100644
--- a/include/QtCrypto/qcaprovider.h
+++ b/include/QtCrypto/qcaprovider.h
@@ -33,10 +33,10 @@
 
 #include <limits>
 
-class QCA_EXPORT QCAPlugin : public QObject
+class QCA_EXPORT QCAPlugin
 {
-	Q_OBJECT
 public:
+	virtual ~QCAPlugin() {}
 	virtual QCA::Provider *createProvider() = 0;
 };
 
diff --git a/plugins/qca-botan/qca-botan.cpp b/plugins/qca-botan/qca-botan.cpp
index 543de9c4..58416ccb 100644
--- a/plugins/qca-botan/qca-botan.cpp
+++ b/plugins/qca-botan/qca-botan.cpp
@@ -458,7 +458,7 @@ private:
 
 };
 
-class botanPlugin : public QCAPlugin
+class botanPlugin : public QObject, public QCAPlugin
 {
 	Q_OBJECT
 	Q_INTERFACES(QCAPlugin)
diff --git a/plugins/qca-cyrus-sasl/qca-cyrus-sasl.cpp b/plugins/qca-cyrus-sasl/qca-cyrus-sasl.cpp
index 529da19a..2df8bdcb 100644
--- a/plugins/qca-cyrus-sasl/qca-cyrus-sasl.cpp
+++ b/plugins/qca-cyrus-sasl/qca-cyrus-sasl.cpp
@@ -895,7 +895,7 @@ using namespace saslQCAPlugin;
 // saslPlugin
 //----------------------------------------------------------------------------
 
-class saslPlugin : public QCAPlugin
+class saslPlugin : public QObject, public QCAPlugin
 {
 	Q_OBJECT
 	Q_INTERFACES(QCAPlugin)
diff --git a/plugins/qca-gcrypt/qca-gcrypt.cpp b/plugins/qca-gcrypt/qca-gcrypt.cpp
index 5f66e9fb..0ac93721 100644
--- a/plugins/qca-gcrypt/qca-gcrypt.cpp
+++ b/plugins/qca-gcrypt/qca-gcrypt.cpp
@@ -574,7 +574,7 @@ public:
     }
 };
 
-class gcryptPlugin : public QCAPlugin
+class gcryptPlugin : public QObject, public QCAPlugin
 {
     Q_OBJECT
     Q_INTERFACES(QCAPlugin)
diff --git a/plugins/qca-gnupg/qca-gnupg.cpp b/plugins/qca-gnupg/qca-gnupg.cpp
index 960375bb..18343cb4 100644
--- a/plugins/qca-gnupg/qca-gnupg.cpp
+++ b/plugins/qca-gnupg/qca-gnupg.cpp
@@ -1001,7 +1001,7 @@ public:
 	}
 };
 
-class gnupgPlugin : public QCAPlugin
+class gnupgPlugin : public QObject, public QCAPlugin
 {
 	Q_OBJECT
 	Q_INTERFACES(QCAPlugin)
diff --git a/plugins/qca-nss/qca-nss.cpp b/plugins/qca-nss/qca-nss.cpp
index f7eb9f1b..7a4f6ac3 100644
--- a/plugins/qca-nss/qca-nss.cpp
+++ b/plugins/qca-nss/qca-nss.cpp
@@ -497,7 +497,7 @@ public:
     }
 };
 
-class nssPlugin : public QCAPlugin
+class nssPlugin : public QObject, public QCAPlugin
 {
 	Q_OBJECT
 	Q_INTERFACES( QCAPlugin )
diff --git a/plugins/qca-openssl/qca-openssl.cpp b/plugins/qca-openssl/qca-openssl.cpp
index e1ef821d..aabc06e8 100644
--- a/plugins/qca-openssl/qca-openssl.cpp
+++ b/plugins/qca-openssl/qca-openssl.cpp
@@ -6223,7 +6223,7 @@ public:
 	}
 };
 
-class opensslPlugin : public QCAPlugin
+class opensslPlugin : public QObject, public QCAPlugin
 {
 	Q_OBJECT
 	Q_INTERFACES(QCAPlugin)
diff --git a/plugins/qca-pkcs11/qca-pkcs11.cpp b/plugins/qca-pkcs11/qca-pkcs11.cpp
index 5cd80e65..4f988284 100644
--- a/plugins/qca-pkcs11/qca-pkcs11.cpp
+++ b/plugins/qca-pkcs11/qca-pkcs11.cpp
@@ -2812,7 +2812,7 @@ pkcs11Provider::pinPromptHook (
 	return ret; //krazy:exclude=captruefalse
 }
 
-class pkcs11Plugin : public QCAPlugin
+class pkcs11Plugin : public QObject, public QCAPlugin
 {
 	Q_OBJECT
 	Q_INTERFACES(QCAPlugin)