diff --git a/Pdf4QtLibCore/sources/pdfcatalog.h b/Pdf4QtLibCore/sources/pdfcatalog.h
index a90a011..17203c1 100644
--- a/Pdf4QtLibCore/sources/pdfcatalog.h
+++ b/Pdf4QtLibCore/sources/pdfcatalog.h
@@ -24,6 +24,8 @@
 #include "pdfoutline.h"
 #include "pdfaction.h"
 
+#include <QtCore>
+
 #include <array>
 #include <vector>
 #include <utility>
diff --git a/Pdf4QtLibCore/sources/pdfcms.cpp b/Pdf4QtLibCore/sources/pdfcms.cpp
index a105808..19de17f 100644
--- a/Pdf4QtLibCore/sources/pdfcms.cpp
+++ b/Pdf4QtLibCore/sources/pdfcms.cpp
@@ -20,10 +20,7 @@
 #include "pdfexecutionpolicy.h"
 #include "pdfdbgheap.h"
 
-#include <QBuffer>
 #include <QCoreApplication>
-#include <QDir>
-#include <QFile>
 #include <QReadWriteLock>
 
 #ifdef PDF4QT_COMPILER_CLANG
diff --git a/Pdf4QtLibCore/sources/pdfdocument.h b/Pdf4QtLibCore/sources/pdfdocument.h
index be96d65..977f825 100644
--- a/Pdf4QtLibCore/sources/pdfdocument.h
+++ b/Pdf4QtLibCore/sources/pdfdocument.h
@@ -23,6 +23,7 @@
 #include "pdfcatalog.h"
 #include "pdfsecurityhandler.h"
 
+#include <QtCore>
 #include <QColor>
 #include <QTransform>
 #include <QDateTime>
diff --git a/Pdf4QtLibCore/sources/pdfdocumentbuilder.h b/Pdf4QtLibCore/sources/pdfdocumentbuilder.h
index fe6c35f..0cd2384 100644
--- a/Pdf4QtLibCore/sources/pdfdocumentbuilder.h
+++ b/Pdf4QtLibCore/sources/pdfdocumentbuilder.h
@@ -23,7 +23,6 @@
 #include "pdfannotation.h"
 
 class QPdfWriter;
-class QBuffer;
 
 namespace pdf
 {
diff --git a/Pdf4QtLibCore/sources/pdfdocumentreader.h b/Pdf4QtLibCore/sources/pdfdocumentreader.h
index 7b02f3f..e3643da 100644
--- a/Pdf4QtLibCore/sources/pdfdocumentreader.h
+++ b/Pdf4QtLibCore/sources/pdfdocumentreader.h
@@ -24,8 +24,8 @@
 #include "pdfprogress.h"
 #include "pdfxreftable.h"
 
+#include <QtCore>
 #include <QIODevice>
-#include <QMutex>
 
 namespace pdf
 {
diff --git a/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp b/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp
index 1564667..df1d6fb 100644
--- a/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp
+++ b/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp
@@ -21,7 +21,6 @@
 #include "pdfparser.h"
 #include "pdfdbgheap.h"
 
-#include <QBuffer>
 #include <QFile>
 #include <QSaveFile>
 
diff --git a/Pdf4QtLibCore/sources/pdffont.cpp b/Pdf4QtLibCore/sources/pdffont.cpp
index 41e7aee..e725b5a 100644
--- a/Pdf4QtLibCore/sources/pdffont.cpp
+++ b/Pdf4QtLibCore/sources/pdffont.cpp
@@ -30,8 +30,6 @@
 #include <freetype/ftoutln.h>
 #include <freetype/t1tables.h>
 
-#include <QFile>
-#include <QIODevice>
 #include <QMutex>
 #include <QReadWriteLock>
 #include <QPainterPath>
diff --git a/Pdf4QtLibCore/sources/pdffont.h b/Pdf4QtLibCore/sources/pdffont.h
index 737b2ae..74a5bbf 100644
--- a/Pdf4QtLibCore/sources/pdffont.h
+++ b/Pdf4QtLibCore/sources/pdffont.h
@@ -23,7 +23,6 @@
 #include "pdfobject.h"
 
 #include <QFont>
-#include <QMutex>
 #include <QTransform>
 #include <QSharedPointer>
 
diff --git a/Pdf4QtLibCore/sources/pdffunction.cpp b/Pdf4QtLibCore/sources/pdffunction.cpp
index bd00627..6694929 100644
--- a/Pdf4QtLibCore/sources/pdffunction.cpp
+++ b/Pdf4QtLibCore/sources/pdffunction.cpp
@@ -23,8 +23,6 @@
 #include "pdfutils.h"
 #include "pdfdbgheap.h"
 
-#include <QIODevice>
-
 #include <stack>
 #include <iterator>
 #include <type_traits>
diff --git a/Pdf4QtLibCore/sources/pdfglobal.h b/Pdf4QtLibCore/sources/pdfglobal.h
index 4c48d43..8645633 100644
--- a/Pdf4QtLibCore/sources/pdfglobal.h
+++ b/Pdf4QtLibCore/sources/pdfglobal.h
@@ -18,8 +18,8 @@
 #ifndef PDFGLOBAL_H
 #define PDFGLOBAL_H
 
+#include <QtCore>
 #include <QtGlobal>
-#include <QCoreApplication>
 
 #include <limits>
 #include <tuple>
diff --git a/Pdf4QtLibCore/sources/pdficontheme.cpp b/Pdf4QtLibCore/sources/pdficontheme.cpp
index 8ca455c..ac66789 100644
--- a/Pdf4QtLibCore/sources/pdficontheme.cpp
+++ b/Pdf4QtLibCore/sources/pdficontheme.cpp
@@ -19,7 +19,6 @@
 #include "pdfdbgheap.h"
 
 #include <QCoreApplication>
-#include <QDir>
 
 namespace pdf
 {
diff --git a/Pdf4QtLibCore/sources/pdfobjectutils.h b/Pdf4QtLibCore/sources/pdfobjectutils.h
index 9b93dcb..52dba51 100644
--- a/Pdf4QtLibCore/sources/pdfobjectutils.h
+++ b/Pdf4QtLibCore/sources/pdfobjectutils.h
@@ -20,6 +20,8 @@
 
 #include "pdfobject.h"
 
+#include <QtCore>
+
 #include <set>
 #include <vector>
 #include <atomic>
diff --git a/Pdf4QtLibCore/sources/pdfpage.h b/Pdf4QtLibCore/sources/pdfpage.h
index 20c8ae9..001e766 100644
--- a/Pdf4QtLibCore/sources/pdfpage.h
+++ b/Pdf4QtLibCore/sources/pdfpage.h
@@ -21,7 +21,6 @@
 #include "pdfobject.h"
 
 #include <QRectF>
-#include <QDateTime>
 
 #include <set>
 #include <optional>
diff --git a/Pdf4QtLibCore/sources/pdfparser.cpp b/Pdf4QtLibCore/sources/pdfparser.cpp
index 679ffe3..934549d 100644
--- a/Pdf4QtLibCore/sources/pdfparser.cpp
+++ b/Pdf4QtLibCore/sources/pdfparser.cpp
@@ -23,7 +23,6 @@
 
 #include <QFile>
 #include <QThread>
-#include <QMetaEnum>
 
 #include <cctype>
 #include <memory>
diff --git a/Pdf4QtLibCore/sources/pdfparser.h b/Pdf4QtLibCore/sources/pdfparser.h
index abcfd16..41f5deb 100644
--- a/Pdf4QtLibCore/sources/pdfparser.h
+++ b/Pdf4QtLibCore/sources/pdfparser.h
@@ -23,6 +23,7 @@
 #include "pdfobject.h"
 #include "pdfflatmap.h"
 
+#include <QtCore>
 #include <QVariant>
 #include <QByteArray>
 
diff --git a/Pdf4QtLibCore/sources/pdfpattern.cpp b/Pdf4QtLibCore/sources/pdfpattern.cpp
index de5a5cd..77de70d 100644
--- a/Pdf4QtLibCore/sources/pdfpattern.cpp
+++ b/Pdf4QtLibCore/sources/pdfpattern.cpp
@@ -24,7 +24,6 @@
 #include "pdfconstants.h"
 #include "pdfdbgheap.h"
 
-#include <QMutex>
 #include <QPainter>
 
 #include <execution>
diff --git a/Pdf4QtLibCore/sources/pdfsecurityhandler.h b/Pdf4QtLibCore/sources/pdfsecurityhandler.h
index adc8b34..32930a5 100644
--- a/Pdf4QtLibCore/sources/pdfsecurityhandler.h
+++ b/Pdf4QtLibCore/sources/pdfsecurityhandler.h
@@ -24,8 +24,6 @@
 #include <QByteArray>
 #include <QSharedPointer>
 
-class QRandomGenerator;
-
 #include <map>
 #include <functional>
 
diff --git a/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp b/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp
index 256f577..42d9262 100644
--- a/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp
+++ b/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp
@@ -40,13 +40,10 @@
 #include <openssl/ts.h>
 #include <openssl/tserr.h>
 
-#include <QDir>
-#include <QLockFile>
 #include <QMutex>
 #include <QMutexLocker>
 #include <QDataStream>
 #include <QFileInfo>
-#include <QStandardPaths>
 
 #include <array>
 #ifdef Q_OS_UNIX
diff --git a/Pdf4QtLibCore/sources/pdftextlayout.cpp b/Pdf4QtLibCore/sources/pdftextlayout.cpp
index d8a0da8..aca2d9c 100644
--- a/Pdf4QtLibCore/sources/pdftextlayout.cpp
+++ b/Pdf4QtLibCore/sources/pdftextlayout.cpp
@@ -20,11 +20,7 @@
 #include "pdfexecutionpolicy.h"
 #include "pdfdbgheap.h"
 
-#include <QIODevice>
-#include <QMutexLocker>
 #include <QPainter>
-#include <QRegularExpressionMatch>
-#include <QRegularExpressionMatchIterator>
 
 #include <execution>
 
diff --git a/Pdf4QtLibCore/sources/pdftextlayout.h b/Pdf4QtLibCore/sources/pdftextlayout.h
index 617d4c6..79983a9 100644
--- a/Pdf4QtLibCore/sources/pdftextlayout.h
+++ b/Pdf4QtLibCore/sources/pdftextlayout.h
@@ -25,8 +25,6 @@
 #include <QDataStream>
 #include <QPainterPath>
 
-class QMutex;
-
 #include <set>
 #include <compare>
 
diff --git a/Pdf4QtLibCore/sources/pdfxfaengine.cpp b/Pdf4QtLibCore/sources/pdfxfaengine.cpp
index 4ae73f2..316200f 100644
--- a/Pdf4QtLibCore/sources/pdfxfaengine.cpp
+++ b/Pdf4QtLibCore/sources/pdfxfaengine.cpp
@@ -21,7 +21,6 @@
 #include "pdffont.h"
 #include "pdfdbgheap.h"
 
-#include <QBuffer>
 #include <QDomElement>
 #include <QDomDocument>
 #include <QStringList>
diff --git a/Pdf4QtLibCore/sources/pdfxreftable.cpp b/Pdf4QtLibCore/sources/pdfxreftable.cpp
index 99ed65f..90d175b 100644
--- a/Pdf4QtLibCore/sources/pdfxreftable.cpp
+++ b/Pdf4QtLibCore/sources/pdfxreftable.cpp
@@ -22,7 +22,6 @@
 #include "pdfstreamfilters.h"
 #include "pdfdbgheap.h"
 
-#include <QIODevice>
 #include <stack>
 
 namespace pdf
diff --git a/Pdf4QtLibCore/sources/pdfxreftable.h b/Pdf4QtLibCore/sources/pdfxreftable.h
index abfa71a..d75f660 100644
--- a/Pdf4QtLibCore/sources/pdfxreftable.h
+++ b/Pdf4QtLibCore/sources/pdfxreftable.h
@@ -21,6 +21,8 @@
 #include "pdfglobal.h"
 #include "pdfobject.h"
 
+#include <QtCore>
+
 #include <vector>
 
 namespace pdf