diff --git a/Pdf4QtDocDiff/utils.h b/Pdf4QtDocDiff/utils.h
index 53a2097..7fb9dda 100644
--- a/Pdf4QtDocDiff/utils.h
+++ b/Pdf4QtDocDiff/utils.h
@@ -23,8 +23,6 @@
 #include "pdfdrawspacecontroller.h"
 #include "pdfdocumentdrawinterface.h"
 
-#include <QtCore>
-
 namespace pdf
 {
 class PDFDocumentBuilder;
diff --git a/Pdf4QtLibCore/CMakeLists.txt b/Pdf4QtLibCore/CMakeLists.txt
index 6f12727..31731b7 100644
--- a/Pdf4QtLibCore/CMakeLists.txt
+++ b/Pdf4QtLibCore/CMakeLists.txt
@@ -16,6 +16,7 @@
 #    along with PDF4QT.  If not, see <https://www.gnu.org/licenses/>.
 
 add_library(Pdf4QtLibCore SHARED
+    sources/pdfglobal.h
     sources/pdfaction.cpp
     sources/pdfaction.h
     sources/pdfalgorithmlcs.cpp
diff --git a/Pdf4QtLibCore/sources/pdfcatalog.h b/Pdf4QtLibCore/sources/pdfcatalog.h
index 17203c1..a90a011 100644
--- a/Pdf4QtLibCore/sources/pdfcatalog.h
+++ b/Pdf4QtLibCore/sources/pdfcatalog.h
@@ -24,8 +24,6 @@
 #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 19de17f..250ac61 100644
--- a/Pdf4QtLibCore/sources/pdfcms.cpp
+++ b/Pdf4QtLibCore/sources/pdfcms.cpp
@@ -20,6 +20,9 @@
 #include "pdfexecutionpolicy.h"
 #include "pdfdbgheap.h"
 
+#include <QDir>
+#include <QFile>
+#include <QBuffer>
 #include <QCoreApplication>
 #include <QReadWriteLock>
 
diff --git a/Pdf4QtLibCore/sources/pdfdocument.h b/Pdf4QtLibCore/sources/pdfdocument.h
index 977f825..be96d65 100644
--- a/Pdf4QtLibCore/sources/pdfdocument.h
+++ b/Pdf4QtLibCore/sources/pdfdocument.h
@@ -23,7 +23,6 @@
 #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 0cd2384..3a5de42 100644
--- a/Pdf4QtLibCore/sources/pdfdocumentbuilder.h
+++ b/Pdf4QtLibCore/sources/pdfdocumentbuilder.h
@@ -22,6 +22,7 @@
 #include "pdfdocument.h"
 #include "pdfannotation.h"
 
+class QBuffer;
 class QPdfWriter;
 
 namespace pdf
diff --git a/Pdf4QtLibCore/sources/pdfdocumentreader.h b/Pdf4QtLibCore/sources/pdfdocumentreader.h
index e3643da..a768567 100644
--- a/Pdf4QtLibCore/sources/pdfdocumentreader.h
+++ b/Pdf4QtLibCore/sources/pdfdocumentreader.h
@@ -24,7 +24,7 @@
 #include "pdfprogress.h"
 #include "pdfxreftable.h"
 
-#include <QtCore>
+#include <QMutex>
 #include <QIODevice>
 
 namespace pdf
diff --git a/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp b/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp
index df1d6fb..b99c278 100644
--- a/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp
+++ b/Pdf4QtLibCore/sources/pdfdocumentwriter.cpp
@@ -22,6 +22,7 @@
 #include "pdfdbgheap.h"
 
 #include <QFile>
+#include <QBuffer>
 #include <QSaveFile>
 
 namespace pdf
diff --git a/Pdf4QtLibCore/sources/pdffont.cpp b/Pdf4QtLibCore/sources/pdffont.cpp
index e725b5a..1a10f2b 100644
--- a/Pdf4QtLibCore/sources/pdffont.cpp
+++ b/Pdf4QtLibCore/sources/pdffont.cpp
@@ -30,6 +30,7 @@
 #include <freetype/ftoutln.h>
 #include <freetype/t1tables.h>
 
+#include <QFile>
 #include <QMutex>
 #include <QReadWriteLock>
 #include <QPainterPath>
diff --git a/Pdf4QtLibCore/sources/pdffont.h b/Pdf4QtLibCore/sources/pdffont.h
index 74a5bbf..737b2ae 100644
--- a/Pdf4QtLibCore/sources/pdffont.h
+++ b/Pdf4QtLibCore/sources/pdffont.h
@@ -23,6 +23,7 @@
 #include "pdfobject.h"
 
 #include <QFont>
+#include <QMutex>
 #include <QTransform>
 #include <QSharedPointer>
 
diff --git a/Pdf4QtLibCore/sources/pdffunction.cpp b/Pdf4QtLibCore/sources/pdffunction.cpp
index 6694929..bd00627 100644
--- a/Pdf4QtLibCore/sources/pdffunction.cpp
+++ b/Pdf4QtLibCore/sources/pdffunction.cpp
@@ -23,6 +23,8 @@
 #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 8645633..475d1ef 100644
--- a/Pdf4QtLibCore/sources/pdfglobal.h
+++ b/Pdf4QtLibCore/sources/pdfglobal.h
@@ -19,7 +19,9 @@
 #define PDFGLOBAL_H
 
 #include <QtCore>
-#include <QtGlobal>
+#include <QtSystemDetection>
+#include <QtCompilerDetection>
+#include <QCoreApplication>
 
 #include <limits>
 #include <tuple>
diff --git a/Pdf4QtLibCore/sources/pdficontheme.cpp b/Pdf4QtLibCore/sources/pdficontheme.cpp
index ac66789..580ac9f 100644
--- a/Pdf4QtLibCore/sources/pdficontheme.cpp
+++ b/Pdf4QtLibCore/sources/pdficontheme.cpp
@@ -18,6 +18,8 @@
 #include "pdficontheme.h"
 #include "pdfdbgheap.h"
 
+#include <QDir>
+#include <QFile>
 #include <QCoreApplication>
 
 namespace pdf
diff --git a/Pdf4QtLibCore/sources/pdfobjectutils.h b/Pdf4QtLibCore/sources/pdfobjectutils.h
index 52dba51..9b93dcb 100644
--- a/Pdf4QtLibCore/sources/pdfobjectutils.h
+++ b/Pdf4QtLibCore/sources/pdfobjectutils.h
@@ -20,8 +20,6 @@
 
 #include "pdfobject.h"
 
-#include <QtCore>
-
 #include <set>
 #include <vector>
 #include <atomic>
diff --git a/Pdf4QtLibCore/sources/pdfpage.h b/Pdf4QtLibCore/sources/pdfpage.h
index 001e766..20c8ae9 100644
--- a/Pdf4QtLibCore/sources/pdfpage.h
+++ b/Pdf4QtLibCore/sources/pdfpage.h
@@ -21,6 +21,7 @@
 #include "pdfobject.h"
 
 #include <QRectF>
+#include <QDateTime>
 
 #include <set>
 #include <optional>
diff --git a/Pdf4QtLibCore/sources/pdfparser.cpp b/Pdf4QtLibCore/sources/pdfparser.cpp
index 934549d..679ffe3 100644
--- a/Pdf4QtLibCore/sources/pdfparser.cpp
+++ b/Pdf4QtLibCore/sources/pdfparser.cpp
@@ -23,6 +23,7 @@
 
 #include <QFile>
 #include <QThread>
+#include <QMetaEnum>
 
 #include <cctype>
 #include <memory>
diff --git a/Pdf4QtLibCore/sources/pdfparser.h b/Pdf4QtLibCore/sources/pdfparser.h
index 41f5deb..abcfd16 100644
--- a/Pdf4QtLibCore/sources/pdfparser.h
+++ b/Pdf4QtLibCore/sources/pdfparser.h
@@ -23,7 +23,6 @@
 #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 77de70d..de5a5cd 100644
--- a/Pdf4QtLibCore/sources/pdfpattern.cpp
+++ b/Pdf4QtLibCore/sources/pdfpattern.cpp
@@ -24,6 +24,7 @@
 #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 32930a5..f55a8a6 100644
--- a/Pdf4QtLibCore/sources/pdfsecurityhandler.h
+++ b/Pdf4QtLibCore/sources/pdfsecurityhandler.h
@@ -27,6 +27,8 @@
 #include <map>
 #include <functional>
 
+class QRandomGenerator;
+
 namespace pdf
 {
 class PDFObjectFactory;
diff --git a/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp b/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp
index 42d9262..3040ccb 100644
--- a/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp
+++ b/Pdf4QtLibCore/sources/pdfsignaturehandler.cpp
@@ -40,10 +40,13 @@
 #include <openssl/ts.h>
 #include <openssl/tserr.h>
 
+#include <QDir>
 #include <QMutex>
-#include <QMutexLocker>
-#include <QDataStream>
 #include <QFileInfo>
+#include <QLockFile>
+#include <QDataStream>
+#include <QMutexLocker>
+#include <QStandardPaths>
 
 #include <array>
 #ifdef Q_OS_UNIX
diff --git a/Pdf4QtLibCore/sources/pdftextlayout.cpp b/Pdf4QtLibCore/sources/pdftextlayout.cpp
index aca2d9c..4c118e6 100644
--- a/Pdf4QtLibCore/sources/pdftextlayout.cpp
+++ b/Pdf4QtLibCore/sources/pdftextlayout.cpp
@@ -20,7 +20,11 @@
 #include "pdfexecutionpolicy.h"
 #include "pdfdbgheap.h"
 
+#include <QMutex>
 #include <QPainter>
+#include <QIODevice>
+#include <QMutexLocker>
+#include <QRegularExpression>
 
 #include <execution>
 
diff --git a/Pdf4QtLibCore/sources/pdftextlayout.h b/Pdf4QtLibCore/sources/pdftextlayout.h
index 79983a9..e63a620 100644
--- a/Pdf4QtLibCore/sources/pdftextlayout.h
+++ b/Pdf4QtLibCore/sources/pdftextlayout.h
@@ -28,6 +28,8 @@
 #include <set>
 #include <compare>
 
+class QMutex;
+
 namespace pdf
 {
 class PDFTextLayout;
diff --git a/Pdf4QtLibCore/sources/pdfxfaengine.cpp b/Pdf4QtLibCore/sources/pdfxfaengine.cpp
index 316200f..4ae73f2 100644
--- a/Pdf4QtLibCore/sources/pdfxfaengine.cpp
+++ b/Pdf4QtLibCore/sources/pdfxfaengine.cpp
@@ -21,6 +21,7 @@
 #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 90d175b..c35a96f 100644
--- a/Pdf4QtLibCore/sources/pdfxreftable.cpp
+++ b/Pdf4QtLibCore/sources/pdfxreftable.cpp
@@ -22,6 +22,8 @@
 #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 d75f660..abfa71a 100644
--- a/Pdf4QtLibCore/sources/pdfxreftable.h
+++ b/Pdf4QtLibCore/sources/pdfxreftable.h
@@ -21,8 +21,6 @@
 #include "pdfglobal.h"
 #include "pdfobject.h"
 
-#include <QtCore>
-
 #include <vector>
 
 namespace pdf
diff --git a/Pdf4QtLibWidgets/sources/pdfcompiler.h b/Pdf4QtLibWidgets/sources/pdfcompiler.h
index 19e46e2..b10ae54 100644
--- a/Pdf4QtLibWidgets/sources/pdfcompiler.h
+++ b/Pdf4QtLibWidgets/sources/pdfcompiler.h
@@ -18,6 +18,7 @@
 #ifndef PDFCOMPILER_H
 #define PDFCOMPILER_H
 
+#include "pdfglobal.h"
 #include "pdfwidgetsglobal.h"
 #include "pdfrenderer.h"
 #include "pdfpainter.h"
diff --git a/Pdf4QtLibWidgets/sources/pdfwidgetsglobal.h b/Pdf4QtLibWidgets/sources/pdfwidgetsglobal.h
index 4b883a2..25e9781 100644
--- a/Pdf4QtLibWidgets/sources/pdfwidgetsglobal.h
+++ b/Pdf4QtLibWidgets/sources/pdfwidgetsglobal.h
@@ -18,8 +18,7 @@
 #ifndef PDFWIDGETSGLOBAL_H
 #define PDFWIDGETSGLOBAL_H
 
-#include <QtCore>
-#include <QtGlobal>
+#include <QtCompilerDetection>
 
 #include <pdf4qtlibwidgets_export.h>
 
@@ -31,5 +30,4 @@
 #endif
 #endif
 
-
 #endif // PDFWIDGETSGLOBAL_H