diff --git a/src/core/scheduler.cpp b/src/core/scheduler.cpp
--- a/src/core/scheduler.cpp
+++ b/src/core/scheduler.cpp
@@ -545,6 +545,7 @@
                              SLOT(slotSlaveDied(KIO::Slave*)));
         scheduler()->connect(slave, SIGNAL(slaveStatus(qint64,QByteArray,QString,bool)),
                              SLOT(slotSlaveStatus(qint64,QByteArray,QString,bool)));
+        m_connectedSlaveQueue.addSlave(slave);
     } else {
         qCWarning(KIO_CORE) << "couldn't create slave:" << errortext;
         if (job) {
diff --git a/src/core/slave.cpp b/src/core/slave.cpp
--- a/src/core/slave.cpp
+++ b/src/core/slave.cpp
@@ -171,7 +171,7 @@
     d->slaveconnserver->deleteLater();
     d->slaveconnserver = nullptr;
 
-    connect(d->connection, SIGNAL(readyRead()), SLOT(gotInput()));
+    connect(d->connection, &Connection::readyRead, this, &Slave::gotInput);
 }
 
 void Slave::timeout()
@@ -218,7 +218,7 @@
     Q_D(Slave);
     d->slaveconnserver->setParent(this);
     d->connection = new Connection(this);
-    connect(d->slaveconnserver, SIGNAL(newConnection()), SLOT(accept()));
+    connect(d->slaveconnserver, &ConnectionServer::newConnection, this, &Slave::accept);
 }
 
 Slave::~Slave()
diff --git a/src/core/slaveinterface_p.h b/src/core/slaveinterface_p.h
--- a/src/core/slaveinterface_p.h
+++ b/src/core/slaveinterface_p.h
@@ -42,7 +42,7 @@
           nums(0), slave_calcs_speed(false)
     {
     }
-    ~SlaveInterfacePrivate()
+    virtual ~SlaveInterfacePrivate()
     {
         delete connection;
     }