diff --git a/libnymea-core/hardware/network/upnp/upnpdiscoveryimplementation.cpp b/libnymea-core/hardware/network/upnp/upnpdiscoveryimplementation.cpp
index 92a1cac8..6f4475b0 100644
--- a/libnymea-core/hardware/network/upnp/upnpdiscoveryimplementation.cpp
+++ b/libnymea-core/hardware/network/upnp/upnpdiscoveryimplementation.cpp
@@ -578,7 +578,7 @@ bool UpnpDiscoveryImplementation::enable()
     m_available = true;
     emit availableChanged(true);
 
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     connect(m_socket, &QUdpSocket::errorOccurred, this, &UpnpDiscoveryImplementation::error);
 #else
     connect(m_socket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(error(QAbstractSocket::SocketError)));
diff --git a/libnymea-core/hardware/radio433/radio433brennenstuhlgateway.cpp b/libnymea-core/hardware/radio433/radio433brennenstuhlgateway.cpp
index 18e1c546..1d24a9bb 100644
--- a/libnymea-core/hardware/radio433/radio433brennenstuhlgateway.cpp
+++ b/libnymea-core/hardware/radio433/radio433brennenstuhlgateway.cpp
@@ -41,7 +41,7 @@ Radio433BrennenstuhlGateway::Radio433BrennenstuhlGateway(QObject *parent) :
     // UDP socket to sending data to gateway
     m_gateway = new QUdpSocket(this);
     connect(m_gateway, &QUdpSocket::readyRead, this, &Radio433BrennenstuhlGateway::readData);
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     connect(m_gateway, &QUdpSocket::errorOccurred, this, &Radio433BrennenstuhlGateway::gatewayError);
 #else
     connect(m_gateway, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(gatewayError(QAbstractSocket::SocketError)));
diff --git a/libnymea-core/servers/webserver.cpp b/libnymea-core/servers/webserver.cpp
index 5782ff81..87f29159 100644
--- a/libnymea-core/servers/webserver.cpp
+++ b/libnymea-core/servers/webserver.cpp
@@ -278,7 +278,7 @@ void WebServer::incomingConnection(qintptr socketDescriptor)
     connect(socket, &QSslSocket::readyRead, this, &WebServer::readClient);
     connect(socket, &QSslSocket::disconnected, this, &WebServer::onDisconnected);
 
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     connect(socket, &QSslSocket::errorOccurred, this, &WebServer::onError);
 #else
     connect(socket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(onError(QAbstractSocket::SocketError)));
@@ -517,7 +517,7 @@ void WebServer::onEncrypted()
     connect(socket, &QSslSocket::readyRead, this, &WebServer::readClient);
     connect(socket, &QSslSocket::disconnected, this, &WebServer::onDisconnected);
 
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     connect(socket, &QSslSocket::errorOccurred, this, &WebServer::onError);
 #else
     connect(socket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(onError(QAbstractSocket::SocketError)));