Three connects paired a zero-argument signal with a slot that has a default-valued parameter (e.g. void applyEnable(bool = true)).

Default arguments aren't part of a function's pointer-to-member type, so &Class::slot has a type requiring the argument regardless of its
default value -- incompatible with a signal providing none, and &Class::slot alone won't compile against these signals at all.
When migrating to the modern member pointer connect, replaced  with a lambda that calls the slot with no arguments, letting
the default apply exactly as before.

- SelectAutonumW::applyEnable(bool = true), connected to each  NumPartEditorW's changed() signal in both setContext() and
  on_add_button_clicked(). The corresponding disconnect() in on_remove_button_clicked() is removed rather than reimplemented: a
  lambda-based connection can't be matched and removed by a  separately-written disconnect() call, and the explicit disconnect
  was already redundant -- the very next line deletes the part object, which Qt automatically disconnects on destruction (the same
  guarantee setContext()'s own qDeleteAll() cleanup already relies  on).
- PartText::adjustItemPosition(int = 0), connected to QTextDocument::contentsChanged().
- ExportDialog::slot_changeFilesExtension(bool = false), connected to ExportPropertiesWidget::formatChanged().

sources/autoNum/ui/selectautonumw.cpp

@@ -112,7 +112,7 @@ void SelectAutonumW::setContext(const NumerotationContext &context)
 	else {
 		for (int i=0; i<m_context.size(); ++i) { //build with the content of @context
 			NumPartEditorW *part= new NumPartEditorW(m_context, i, m_edited_type, this);
-			connect (part, SIGNAL(changed()), this, SLOT(applyEnable()));
+			connect(part, &NumPartEditorW::changed, this, [this]() { applyEnable(); });
 			num_part_list_ << part;
 			ui -> editor_layout -> addWidget(part);
 		}
@@ -145,7 +145,7 @@ void SelectAutonumW::on_add_button_clicked()
 {
 	applyEnable(false);
 	NumPartEditorW *part = new NumPartEditorW(m_edited_type, this);
-	connect (part, SIGNAL(changed()), this, SLOT(applyEnable()));
+	connect(part, &NumPartEditorW::changed, this, [this]() { applyEnable(); });
 	num_part_list_ << part;
 	ui -> editor_layout -> addWidget(part);
 	ui -> remove_button -> setEnabled(true);
@@ -160,7 +160,7 @@ void SelectAutonumW::on_remove_button_clicked()
 	//remove if @num_part_list contains more than one item
 	if (num_part_list_.size() > 1) {
 		NumPartEditorW *part = num_part_list_.takeLast();
-		disconnect(part, SIGNAL(changed()), this, SLOT(applyEnable()));
+		// deliberately not disconnecting as not possible to resolve with lambda and will happen automatically when the object "part" is destroyed.
 		delete part;
 		if (num_part_list_.size() == 1) {
 			ui -> remove_button -> setDisabled(true);

sources/editor/graphicspart/parttext.cpp

@@ -55,9 +55,9 @@ PartText::PartText(QETElementEditor *editor, QGraphicsItem *parent) :
 		this, 
 		&PartText::adjustItemPosition);
 	connect(document(),
-		SIGNAL(contentsChanged()),
+		&QTextDocument::contentsChanged,
 		this,
-		SLOT(adjustItemPosition()));
+		[this]() { adjustItemPosition(); });
 }
 
 /// Destructeur

sources/exportdialog.cpp

@@ -98,7 +98,7 @@ ExportDialog::ExportDialog(
 	layout -> addWidget(buttons);
 	
 	// connexions signaux/slots
-	connect(epw,     SIGNAL(formatChanged()),       this, SLOT(slot_changeFilesExtension()));
+	connect(epw, &ExportPropertiesWidget::formatChanged, this, [this]() { slot_changeFilesExtension(); });
 	connect(epw, &ExportPropertiesWidget::exportedAreaChanged, this, &ExportDialog::slot_changeUseBorder);
 	connect(buttons, &QDialogButtonBox::accepted, this, &ExportDialog::slot_export);
 	connect(buttons, &QDialogButtonBox::rejected, this, &ExportDialog::reject);