diff --git a/RedPandaIDE/RedPandaIDE.pro b/RedPandaIDE/RedPandaIDE.pro
index da093d2b..0e11f3bf 100644
--- a/RedPandaIDE/RedPandaIDE.pro
+++ b/RedPandaIDE/RedPandaIDE.pro
@@ -1,7 +1,6 @@
 QT       += core gui printsupport network svg xml widgets
 
-# without `c++14` old versions of qmake will explicitly set `-std=gnu++98`
-CONFIG += c++14 c++17
+CONFIG += c++17
 CONFIG += nokey
 
 # uncomment the following line to enable vcs (git) support
diff --git a/RedPandaIDE/compiler/compilermanager.cpp b/RedPandaIDE/compiler/compilermanager.cpp
index 6339ddf1..6cc8efd0 100644
--- a/RedPandaIDE/compiler/compilermanager.cpp
+++ b/RedPandaIDE/compiler/compilermanager.cpp
@@ -37,15 +37,9 @@
 #endif
 
 CompilerManager::CompilerManager(QObject *parent) : QObject(parent),
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     mCompileMutex(),
     mBackgroundSyntaxCheckMutex(),
     mRunnerMutex()
-#else
-    mCompileMutex(QMutex::Recursive),
-    mBackgroundSyntaxCheckMutex(QMutex::Recursive),
-    mRunnerMutex(QMutex::Recursive)
-#endif
 {
     mCompiler = nullptr;
     mBackgroundSyntaxChecker = nullptr;
diff --git a/RedPandaIDE/compiler/compilermanager.h b/RedPandaIDE/compiler/compilermanager.h
index bcf541d8..af657806 100644
--- a/RedPandaIDE/compiler/compilermanager.h
+++ b/RedPandaIDE/compiler/compilermanager.h
@@ -104,15 +104,9 @@ private:
     Compiler* mBackgroundSyntaxChecker;
     Runner* mRunner;
     PNonExclusiveTemporaryFileOwner mTempFileOwner;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mCompileMutex;
     QRecursiveMutex mBackgroundSyntaxCheckMutex;
     QRecursiveMutex mRunnerMutex;
-#else
-    QMutex mCompileMutex;
-    QMutex mBackgroundSyntaxCheckMutex;
-    QMutex mRunnerMutex;
-#endif
 };
 
 class CompileError : public BaseError {
diff --git a/RedPandaIDE/debugger/debugger.cpp b/RedPandaIDE/debugger/debugger.cpp
index 5315ee41..8e5297f1 100644
--- a/RedPandaIDE/debugger/debugger.cpp
+++ b/RedPandaIDE/debugger/debugger.cpp
@@ -1108,11 +1108,7 @@ bool Debugger::executing() const
 }
 
 DebuggerClient::DebuggerClient(Debugger* debugger, QObject *parent) : QThread(parent),
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     mCmdQueueMutex(),
-#else
-    mCmdQueueMutex(QMutex::Recursive),
-#endif
     mStartSemaphore(0)
 {
     mDebugger = debugger;
@@ -2469,11 +2465,7 @@ void MemoryModel::updateMemory(const QStringList &value)
     QList<PMemoryLine> newModel;
     for (int i=0;i<value.length();i++) {
         QString line = value[i].trimmed();
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
         QStringList dataLst = line.split(delimiter,Qt::SkipEmptyParts);
-#else
-        QStringList dataLst = line.split(delimiter,QString::SkipEmptyParts);
-#endif
         PMemoryLine memoryLine = std::make_shared<MemoryLine>();
         memoryLine->startAddress = -1;
         if (dataLst.length()>0) {
diff --git a/RedPandaIDE/debugger/debugger.h b/RedPandaIDE/debugger/debugger.h
index d084fe70..0df7985a 100644
--- a/RedPandaIDE/debugger/debugger.h
+++ b/RedPandaIDE/debugger/debugger.h
@@ -595,11 +595,7 @@ signals:
                          bool hasMore);
     void varsValueUpdated();
 protected:
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mCmdQueueMutex;
-#else
-    QMutex mCmdQueueMutex;
-#endif
 
     bool mCmdRunning;
 
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index 70f8afc2..884e6b76 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -3564,7 +3564,6 @@ void Editor::showCompletion(const QString& preWord,bool autoComplete, CodeComple
 
     // Position it at the top of the next line
     QPoint popupPos = mapToGlobal(displayCoordToPixels(displayXY()));
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QSize  desktopSize = screen()->virtualSize();
     if (desktopSize.height() - popupPos.y() < mCompletionPopup->height() && popupPos.y() > mCompletionPopup->height())
         popupPos-=QPoint(0, mCompletionPopup->height()+2);
@@ -3574,9 +3573,6 @@ void Editor::showCompletion(const QString& preWord,bool autoComplete, CodeComple
     if (desktopSize.width() -  popupPos.x() < mCompletionPopup->width() ) {
         popupPos.setX(std::max(0, desktopSize.width()-mCompletionPopup->width())-10);
     }
-#else
-    popupPos+=QPoint(0,textHeight()+2);
-#endif
 
     mCompletionPopup->move(popupPos);
 
@@ -4560,13 +4556,8 @@ void Editor::cancelHoverLink()
 
 QSize Editor::calcCompletionPopupSize()
 {
-#if QT_VERSION_MAJOR==5 && QT_VERSION_MINOR < 15
-    int screenHeight = qApp->primaryScreen()->size().height();
-    int screenWidth = qApp->primaryScreen()->size().width();
-#else
     int screenHeight = screen()->size().height();
     int screenWidth = screen()->size().width();
-#endif
     int popWidth = std::min(pSettings->codeCompletion().widthInColumns() * charWidth(),
                             screenWidth / 2) + 4;
     int popHeight = std::min(pSettings->codeCompletion().heightInLines() * textHeight(),
diff --git a/RedPandaIDE/main.cpp b/RedPandaIDE/main.cpp
index cd3c1def..9c5a183c 100644
--- a/RedPandaIDE/main.cpp
+++ b/RedPandaIDE/main.cpp
@@ -413,12 +413,8 @@ int main(int argc, char *argv[])
 
         MainWindow mainWindow;
         pMainWindow = &mainWindow;
-#if QT_VERSION_MAJOR==5 && QT_VERSION_MINOR < 15
-        setScreenDPI(qApp->primaryScreen()->logicalDotsPerInch());
-#else
         if (mainWindow.screen())
             setScreenDPI(mainWindow.screen()->logicalDotsPerInch());
-#endif
         mainWindow.show();
         if (app.arguments().count()>1) {
             QStringList filesToOpen = app.arguments();
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index d5705040..d764b721 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -4645,12 +4645,7 @@ void MainWindow::onFilesViewCreateFile()
         fileName = QString("untitled%1").arg(count)+suffix;
     }
     QFile file(dir.filePath(fileName));
-#if QT_VERSION >= QT_VERSION_CHECK(5, 11, 0)
     file.open(QFile::NewOnly);
-#else
-    // workaround: try create but do not truncate
-    file.open(QFile::ReadWrite);
-#endif
     file.close();
     QModelIndex newIndex = mFileSystemModel.index(dir.filePath(fileName));
     connect(&mFileSystemModel,&QFileSystemModel::directoryLoaded,
@@ -7716,19 +7711,11 @@ void MainWindow::doFilesViewRemoveFile(const QModelIndex &index)
                                       + tr("Do you really want to delete it?"),
                             QMessageBox::Yes | QMessageBox::No, QMessageBox::No)!=QMessageBox::Yes)
             return;
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,2)
         if (!QFile::moveToTrash(dir.absolutePath()))
             dir.removeRecursively();
-#else
-        dir.removeRecursively();
-#endif
     } else {
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,2)
         if (!QFile::moveToTrash(mFileSystemModel.filePath(index)))
             QFile::remove(mFileSystemModel.filePath(index));
-#else
-        QFile::remove(mFileSystemModel.filePath(index));
-#endif
     }
 }
 
diff --git a/RedPandaIDE/parser/cppparser.cpp b/RedPandaIDE/parser/cppparser.cpp
index 5c6e6025..26bdb838 100644
--- a/RedPandaIDE/parser/cppparser.cpp
+++ b/RedPandaIDE/parser/cppparser.cpp
@@ -39,11 +39,7 @@ static QString calcFullname(const QString& parentName, const QString& name) {
 }
 
 CppParser::CppParser(QObject *parent) : QObject(parent),
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     mMutex()
-#else
-    mMutex(QMutex::Recursive)
-#endif
 {
     mParserId = cppParserCount.fetchAndAddRelaxed(1);
     mLanguage = ParserLanguage::CPlusPlus;
@@ -6659,12 +6655,7 @@ void CppParser::setLanguage(ParserLanguage newLanguage)
         mCppTypeKeywords = CppTypeKeywords;
 #ifdef ENABLE_SDCC
         if (mLanguage == ParserLanguage::SDCC) {
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
             mCppKeywords.insert(SDCCKeywords);
-#else
-            for (auto &k : SDCCKeywords.keys())
-                mCppKeywords[k] = SDCCKeywords[k];
-#endif
             mCppTypeKeywords.unite(SDCCTypeKeywords);
         }
 #endif
diff --git a/RedPandaIDE/parser/cppparser.h b/RedPandaIDE/parser/cppparser.h
index 6a8d9f25..b7d7f5cb 100644
--- a/RedPandaIDE/parser/cppparser.h
+++ b/RedPandaIDE/parser/cppparser.h
@@ -729,11 +729,7 @@ private:
 #ifdef QT_DEBUG
     int mLastIndex;
 #endif
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mMutex;
-#else
-    QMutex mMutex;
-#endif
     QMap<QString,KeywordType> mCppKeywords;
     QSet<QString> mCppTypeKeywords;
 };
diff --git a/RedPandaIDE/parser/cpppreprocessor.cpp b/RedPandaIDE/parser/cpppreprocessor.cpp
index 46164dbe..1399820c 100644
--- a/RedPandaIDE/parser/cpppreprocessor.cpp
+++ b/RedPandaIDE/parser/cpppreprocessor.cpp
@@ -195,12 +195,7 @@ void CppPreprocessor::dumpDefinesTo(const QString &fileName) const
         for (const PDefine& define:mDefines) {
             stream<<QString("%1 %2 %3 %4 %5\n")
                     .arg(define->name,define->args,define->value)
-                    .arg(define->hardCoded).arg(define->formatValue)
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                 <<Qt::endl;
-#else
-                 <<endl;
-#endif
+                    .arg(define->hardCoded).arg(define->formatValue)<<Qt::endl;
         }
     }
 }
@@ -211,25 +206,10 @@ void CppPreprocessor::dumpIncludesListTo(const QString &fileName) const
     if (file.open(QIODevice::WriteOnly|QIODevice::Truncate)) {
         QTextStream stream(&file);
         for (const PParsedFileInfo& fileInfo:mFileInfos) {
-            stream<<fileInfo->fileName()<<" : "
-        #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                         <<Qt::endl;
-        #else
-                         <<endl;
-        #endif
-            stream<<"\t**includes:**"
-        #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                         <<Qt::endl;
-        #else
-                         <<endl;
-        #endif
+            stream<<fileInfo->fileName()<<" : "<<Qt::endl;
+            stream<<"\t**includes:**"<<Qt::endl;
             foreach (const QString& s,fileInfo->includes()) {
-                stream<<"\t--"+s
-        #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                         <<Qt::endl;
-        #else
-                         <<endl;
-        #endif
+                stream<<"\t--"+s<<Qt::endl;
             }
         }
     }
diff --git a/RedPandaIDE/parser/cpptokenizer.cpp b/RedPandaIDE/parser/cpptokenizer.cpp
index 4d9581d7..9adf1284 100644
--- a/RedPandaIDE/parser/cpptokenizer.cpp
+++ b/RedPandaIDE/parser/cpptokenizer.cpp
@@ -83,12 +83,7 @@ void CppTokenizer::dumpTokens(const QString &fileName)
     if (file.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
         QTextStream stream(&file);
         foreach (const PToken& token,mTokenList) {
-            stream<<QString("%1,%2,%3").arg(token->line).arg(token->text).arg(token->matchIndex)
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                 <<Qt::endl;
-#else
-                 <<endl;
-#endif
+            stream<<QString("%1,%2,%3").arg(token->line).arg(token->text).arg(token->matchIndex)<<Qt::endl;
         }
     }
 }
diff --git a/RedPandaIDE/parser/statementmodel.cpp b/RedPandaIDE/parser/statementmodel.cpp
index 04a5ecfa..84a64911 100644
--- a/RedPandaIDE/parser/statementmodel.cpp
+++ b/RedPandaIDE/parser/statementmodel.cpp
@@ -84,12 +84,7 @@ void StatementModel::dumpAll(const QString &logFile)
              .arg(statement->fileName)
              .arg(statement->line)
              .arg(statement->definitionFileName)
-             .arg(statement->definitionLine)<<
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                 Qt::endl;
-#else
-                 endl;
-#endif
+             .arg(statement->definitionLine)<<Qt::endl;
         }
     }
 }
@@ -130,27 +125,12 @@ void StatementModel::dumpStatementMap(StatementMap &map, QTextStream &out, int l
          .arg(statement->line)
          .arg(statement->definitionFileName)
          .arg(statement->definitionLine);
-        out
-        #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                         <<Qt::endl;
-        #else
-                         <<endl;
-        #endif
+        out<<Qt::endl;
         if (statement->children.isEmpty())
             continue;
-        out<<indent<<statement->command<<" {"
-     #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                      <<Qt::endl;
-     #else
-                      <<endl;
-     #endif
+        out<<indent<<statement->command<<" {"<<Qt::endl;
         dumpStatementMap(statement->children,out,level+1);
-        out<<indent<<"}"
-     #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                      <<Qt::endl;
-     #else
-                      <<endl;
-     #endif
+        out<<indent<<"}"<<Qt::endl;
 
     }
 }
diff --git a/RedPandaIDE/project.cpp b/RedPandaIDE/project.cpp
index 091b1e13..b85c7d5d 100644
--- a/RedPandaIDE/project.cpp
+++ b/RedPandaIDE/project.cpp
@@ -538,12 +538,8 @@ bool Project::internalRemoveUnit(PProjectUnit& unit, bool doClose , bool removeF
     }
 
     if (removeFile) {
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,2)
         if (!QFile::moveToTrash(unit->fileName()))
             QFile::remove(unit->fileName());
-#else
-        QFile::remove(unit->fileName());
-#endif
     }
 
 //if not fUnits.GetItem(index).fNew then
@@ -1635,13 +1631,7 @@ void Project::checkProjectFileForUpdate(SimpleIni &ini)
     if (!oldRes.isEmpty()) {
         QFile::copy(mFilename,mFilename+".bak");
         QStringList sl;
-        sl = oldRes.split(';',
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-            Qt::SkipEmptyParts
-#else
-            QString::SkipEmptyParts
-#endif
-                          );
+        sl = oldRes.split(';', Qt::SkipEmptyParts);
         for (int i=0;i<sl.count();i++){
             const QString& s = sl[i];
             QByteArray groupName = toByteArray(QString("Unit%1").arg(uCount+i));
@@ -1992,42 +1982,12 @@ void Project::loadOptions(SimpleIni& ini)
         mOptions.cppCompilerCmd = fromByteArray(ini.GetValue("Project", "CppCompiler", "")).replace(";CONFIG_LINE;","\n");
         mOptions.linkerCmd = fromByteArray(ini.GetValue("Project", "Linker", "")).replace(";CONFIG_LINE;","\n");
         mOptions.resourceCmd = fromByteArray(ini.GetValue("Project", "ResourceCommand", "")).replace(";CONFIG_LINE;","\n");
-        mOptions.binDirs = absolutePaths(fromByteArray(ini.GetValue("Project", "Bins", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-            Qt::SkipEmptyParts
-#else
-            QString::SkipEmptyParts
-#endif
-        ));
-        mOptions.libDirs = absolutePaths(fromByteArray(ini.GetValue("Project", "Libs", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-            Qt::SkipEmptyParts
-#else
-            QString::SkipEmptyParts
-#endif
-        ));
-        mOptions.includeDirs = absolutePaths(fromByteArray(ini.GetValue("Project", "Includes", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-            Qt::SkipEmptyParts
-#else
-            QString::SkipEmptyParts
-#endif
-        ));
+        mOptions.binDirs = absolutePaths(fromByteArray(ini.GetValue("Project", "Bins", "")).split(";", Qt::SkipEmptyParts));
+        mOptions.libDirs = absolutePaths(fromByteArray(ini.GetValue("Project", "Libs", "")).split(";", Qt::SkipEmptyParts));
+        mOptions.includeDirs = absolutePaths(fromByteArray(ini.GetValue("Project", "Includes", "")).split(";", Qt::SkipEmptyParts));
         mOptions.privateResource = fromByteArray(ini.GetValue("Project", "PrivateResource", ""));
-        mOptions.resourceIncludes = absolutePaths(fromByteArray(ini.GetValue("Project", "ResourceIncludes", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-         Qt::SkipEmptyParts
-#else
-         QString::SkipEmptyParts
-#endif
-        ));
-        mOptions.makeIncludes = absolutePaths(fromByteArray(ini.GetValue("Project", "MakeIncludes", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-         Qt::SkipEmptyParts
-#else
-         QString::SkipEmptyParts
-#endif
-        ));
+        mOptions.resourceIncludes = absolutePaths(fromByteArray(ini.GetValue("Project", "ResourceIncludes", "")).split(";", Qt::SkipEmptyParts));
+        mOptions.makeIncludes = absolutePaths(fromByteArray(ini.GetValue("Project", "MakeIncludes", "")).split(";", Qt::SkipEmptyParts));
         mOptions.isCpp = ini.GetBoolValue("Project", "IsCpp", false);
         mOptions.folderForOutput = generateAbsolutePath(directory(), fromByteArray(ini.GetValue("Project", "ExeOutput", "")));
         mOptions.folderForObjFiles =  generateAbsolutePath(directory(), fromByteArray(ini.GetValue("Project", "ObjectOutput", "")));
@@ -2041,13 +2001,7 @@ void Project::loadOptions(SimpleIni& ini)
         mOptions.usePrecompiledHeader = ini.GetBoolValue("Project", "UsePrecompiledHeader", false);
         mOptions.precompiledHeader = generateAbsolutePath(directory(),fromByteArray(ini.GetValue("Project", "PrecompiledHeader", "")));
         mOptions.cmdLineArgs = fromByteArray(ini.GetValue("Project", "CommandLine", ""));
-        mFolders = fromByteArray(ini.GetValue("Project", "Folders", "")).split(";",
-        #if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-                   Qt::SkipEmptyParts
-        #else
-                   QString::SkipEmptyParts
-        #endif
-               );
+        mFolders = fromByteArray(ini.GetValue("Project", "Folders", "")).split(";", Qt::SkipEmptyParts);
         mOptions.includeVersionInfo = ini.GetBoolValue("Project", "IncludeVersionInfo", false);
         mOptions.supportXPThemes = ini.GetBoolValue("Project", "SupportXPThemes", false);
         mOptions.compilerSet = ini.GetLongValue("Project", "CompilerSet", pSettings->compilerSets().defaultIndex());
diff --git a/RedPandaIDE/projecttemplate.cpp b/RedPandaIDE/projecttemplate.cpp
index 077503bf..9ac2c4ed 100644
--- a/RedPandaIDE/projecttemplate.cpp
+++ b/RedPandaIDE/projecttemplate.cpp
@@ -115,36 +115,12 @@ void ProjectTemplate::readTemplateFile(const QString &fileName)
 
     mOptions.icon = mIni->GetValue("Project", "Icon", "");
     mOptions.type = static_cast<ProjectType>(mIni->GetLongValue("Project", "Type", 0)); // default = gui
-    mOptions.includeDirs = fromByteArray(mIni->GetValue("Project", "Includes", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-          Qt::SkipEmptyParts
-#else
-          QString::SkipEmptyParts
-#endif
-      );
-    mOptions.binDirs = fromByteArray(mIni->GetValue("Project", "Bins", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-          Qt::SkipEmptyParts
-#else
-          QString::SkipEmptyParts
-#endif
-      );
+    mOptions.includeDirs = fromByteArray(mIni->GetValue("Project", "Includes", "")).split(";", Qt::SkipEmptyParts);
+    mOptions.binDirs = fromByteArray(mIni->GetValue("Project", "Bins", "")).split(";", Qt::SkipEmptyParts);
 
-    mOptions.libDirs = fromByteArray(mIni->GetValue("Project", "Libs", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-          Qt::SkipEmptyParts
-#else
-          QString::SkipEmptyParts
-#endif
-      );
+    mOptions.libDirs = fromByteArray(mIni->GetValue("Project", "Libs", "")).split(";", Qt::SkipEmptyParts);
 
-    mOptions.resourceIncludes = fromByteArray(mIni->GetValue("Project", "ResourceIncludes", "")).split(";",
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-           Qt::SkipEmptyParts
-#else
-           QString::SkipEmptyParts
-#endif
-       );
+    mOptions.resourceIncludes = fromByteArray(mIni->GetValue("Project", "ResourceIncludes", "")).split(";", Qt::SkipEmptyParts);
     mOptions.compilerCmd = fromByteArray(mIni->GetValue("Project", "Compiler", ""));
     mOptions.cppCompilerCmd = fromByteArray(mIni->GetValue("Project", "CppCompiler", ""));
     mOptions.linkerCmd = fromByteArray(mIni->GetValue("Project", "Linker",""));
diff --git a/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp b/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
index 796e5b38..f0a274fc 100644
--- a/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
+++ b/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
@@ -147,12 +147,7 @@ void ProjectGeneralWidget::doSave()
 
     project->options().isCpp = ui->cbDefaultCpp->isChecked();
     project->options().supportXPThemes = ui->cbSupportXPTheme->isChecked();
-    if (mIconPath.isEmpty()
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-            || ui->lbIcon->pixmap(Qt::ReturnByValue).isNull()) {
-#else
-            || !ui->lbIcon->pixmap() || ui->lbIcon->pixmap()->isNull()) {
-#endif
+    if (mIconPath.isEmpty() || ui->lbIcon->pixmap(Qt::ReturnByValue).isNull()) {
         project->options().icon = "";
     } else {
         QString iconPath = generateAbsolutePath(project->directory(),"app.ico");
@@ -168,11 +163,7 @@ void ProjectGeneralWidget::doSave()
                 }
             }
             if (!mIconPath.endsWith(".ico",PATH_SENSITIVITY) && QImageWriter::supportedImageFormats().contains("ico")) {
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
                 ui->lbIcon->pixmap(Qt::ReturnByValue).save(iconPath,"ico");
-#else
-                ui->lbIcon->pixmap()->save(iconPath,"ico");
-#endif
             } else
                 copyFile(mIconPath, iconPath,true);
         }
diff --git a/RedPandaIDE/todoparser.cpp b/RedPandaIDE/todoparser.cpp
index 0a00500a..4b65a6a1 100644
--- a/RedPandaIDE/todoparser.cpp
+++ b/RedPandaIDE/todoparser.cpp
@@ -24,11 +24,7 @@
 
 static QRegularExpression todoReg("\\b(todo|fixme)\\b", QRegularExpression::CaseInsensitiveOption);
 TodoParser::TodoParser(QObject *parent) : QObject(parent),
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     mMutex()
-#else
-    mMutex(QMutex::Recursive)
-#endif
 {
     mThread = nullptr;
 }
diff --git a/RedPandaIDE/todoparser.h b/RedPandaIDE/todoparser.h
index f72394b1..82066ebe 100644
--- a/RedPandaIDE/todoparser.h
+++ b/RedPandaIDE/todoparser.h
@@ -100,11 +100,7 @@ public:
 
 private:
     TodoThread* mThread;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mMutex;
-#else
-    QMutex mMutex;
-#endif
 };
 
 using PTodoParser = std::shared_ptr<TodoParser>;
diff --git a/RedPandaIDE/widgets/classbrowser.cpp b/RedPandaIDE/widgets/classbrowser.cpp
index 80d96152..09a34236 100644
--- a/RedPandaIDE/widgets/classbrowser.cpp
+++ b/RedPandaIDE/widgets/classbrowser.cpp
@@ -26,11 +26,7 @@
 #include "../iconsmanager.h"
 
 ClassBrowserModel::ClassBrowserModel(QObject *parent):QAbstractItemModel(parent),
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     mMutex()
-#else
-    mMutex(QMutex::Recursive)
-#endif
 {
     mClassBrowserType = ProjectClassBrowserType::CurrentFile;
     mRoot = new ClassBrowserNode();
diff --git a/RedPandaIDE/widgets/classbrowser.h b/RedPandaIDE/widgets/classbrowser.h
index ef4db137..6ba9dc02 100644
--- a/RedPandaIDE/widgets/classbrowser.h
+++ b/RedPandaIDE/widgets/classbrowser.h
@@ -86,11 +86,7 @@ private:
     PCppParser mParser;
     bool mUpdating;
     int mUpdateCount;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mMutex;
-#else
-    QMutex mMutex;
-#endif
     QString mCurrentFile;
     std::shared_ptr<QHash<StatementKind, std::shared_ptr<ColorSchemeItem> > > mColors;
     ProjectClassBrowserType mClassBrowserType;
diff --git a/RedPandaIDE/widgets/codecompletionpopup.cpp b/RedPandaIDE/widgets/codecompletionpopup.cpp
index b5f4d4a2..e192b03f 100644
--- a/RedPandaIDE/widgets/codecompletionpopup.cpp
+++ b/RedPandaIDE/widgets/codecompletionpopup.cpp
@@ -32,11 +32,7 @@
 
 CodeCompletionPopup::CodeCompletionPopup(QWidget *parent) :
     QWidget(parent),
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     mMutex()
-#else
-    mMutex(QMutex::Recursive)
-#endif
 {
     setWindowFlags(Qt::Popup);
     mListView = new CodeCompletionListView(this);
diff --git a/RedPandaIDE/widgets/codecompletionpopup.h b/RedPandaIDE/widgets/codecompletionpopup.h
index 3593e5ef..3ca8953a 100644
--- a/RedPandaIDE/widgets/codecompletionpopup.h
+++ b/RedPandaIDE/widgets/codecompletionpopup.h
@@ -183,11 +183,7 @@ private:
     QSet<QString> mAddedStatements;
     QString mMemberPhrase;
     QString mMemberOperator;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mMutex;
-#else
-    QMutex mMutex;
-#endif
     std::shared_ptr<QHash<StatementKind, std::shared_ptr<ColorSchemeItem> > > mColors;
     CodeCompletionListItemDelegate* mDelegate;
 
diff --git a/RedPandaIDE/widgets/newprojectdialog.cpp b/RedPandaIDE/widgets/newprojectdialog.cpp
index 1057bdf7..dfc04f16 100644
--- a/RedPandaIDE/widgets/newprojectdialog.cpp
+++ b/RedPandaIDE/widgets/newprojectdialog.cpp
@@ -31,9 +31,7 @@ NewProjectDialog::NewProjectDialog(QWidget *parent) :
 {
     setWindowFlag(Qt::WindowContextHelpButtonHint,false);
     ui->setupUi(this);
-#if QT_VERSION >= QT_VERSION_CHECK(5, 12, 0)
     ui->lstTemplates->setItemAlignment(Qt::AlignCenter);
-#endif
     mTemplatesTabBar = new QTabBar(this);
     mTemplatesTabBar->setExpanding(false);
     ui->verticalLayout->insertWidget(0,mTemplatesTabBar);
diff --git a/libs/qsynedit/qsynedit.pro b/libs/qsynedit/qsynedit.pro
index 2bea26ff..60b03dd2 100644
--- a/libs/qsynedit/qsynedit.pro
+++ b/libs/qsynedit/qsynedit.pro
@@ -2,8 +2,7 @@ TEMPLATE = lib
 QT += core gui
 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
-# without `c++14` old versions of qmake will explicitly set `-std=gnu++98`
-CONFIG += c++14 c++17
+CONFIG += c++17
 CONFIG += nokey
 CONFIG += staticlib
 contains(QMAKE_HOST.arch, x86_64):{
diff --git a/libs/qsynedit/qsynedit/document.cpp b/libs/qsynedit/qsynedit/document.cpp
index 229315dd..1b2c0d9b 100644
--- a/libs/qsynedit/qsynedit/document.cpp
+++ b/libs/qsynedit/qsynedit/document.cpp
@@ -36,11 +36,7 @@ Document::Document(const QFont& font, QObject *parent):
     mForceMonospace{false},
     mSetLineWidthLockCount{0},
     mMaxLineChangedInSetLinesWidth{false},
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
-      mMutex{}
-#else
-      mMutex{QMutex::Recursive}
-#endif
+    mMutex{}
 {
     mAppendNewLineAtEOF = true;
     mNewlineType = NewlineType::Windows;
diff --git a/libs/qsynedit/qsynedit/document.h b/libs/qsynedit/qsynedit/document.h
index 811f7f94..7f549ac4 100644
--- a/libs/qsynedit/qsynedit/document.h
+++ b/libs/qsynedit/qsynedit/document.h
@@ -621,11 +621,7 @@ private:
 
     int mSetLineWidthLockCount;
     bool mMaxLineChangedInSetLinesWidth;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     QRecursiveMutex mMutex;
-#else
-    QMutex mMutex;
-#endif
 
     friend class QSynEditPainter;
 };
diff --git a/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp b/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp
index 763bcd9b..9553696d 100644
--- a/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp
+++ b/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp
@@ -147,11 +147,7 @@ QString RTFExporter::getFormatName()
 QString RTFExporter::getHeader()
 {
     QFontMetrics fm(mFont);
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)    
     int tabWidth = mTabSize * fm.horizontalAdvance("M")*72*20/fm.fontDpi();
-#else  
-    int tabWidth = mTabSize * fm.horizontalAdvance("M")*72*20/96;
-#endif
 
     QString result = QString("{\\rtf1\\ansi\\deff0\\deftab%1").arg(tabWidth) + getFontTable();
     // all the colors
diff --git a/libs/qsynedit/qsynedit/syntaxer/asm.cpp b/libs/qsynedit/qsynedit/syntaxer/asm.cpp
index 7c537a77..a889f1d9 100644
--- a/libs/qsynedit/qsynedit/syntaxer/asm.cpp
+++ b/libs/qsynedit/qsynedit/syntaxer/asm.cpp
@@ -1565,14 +1565,7 @@ void ASMSyntaxer::initData()
         Instructions.insert("vxorps",QObject::tr("Bitwise Logical XOR for Single-Precision Floating-Point Values."));
         Instructions.insert("vpclmulqdq",QObject::tr("Carry-Less Multiplication Quadword, Requires PCLMULQDQ CPUID-flag."));
 #endif
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
         InstructionNames=QSet<QString>(Instructions.keyBegin(),Instructions.keyEnd());
-#else
-        InstructionNames.clear();
-        foreach(const QString& s,Instructions.keys()) {
-            InstructionNames.insert(s);
-        }
-#endif
     }
 }
 
diff --git a/libs/redpanda_qt_utils/qt_utils/utils.cpp b/libs/redpanda_qt_utils/qt_utils/utils.cpp
index 3e8722dd..a183cd72 100644
--- a/libs/redpanda_qt_utils/qt_utils/utils.cpp
+++ b/libs/redpanda_qt_utils/qt_utils/utils.cpp
@@ -400,12 +400,7 @@ bool stringsToFile(const QStringList &list, const QString &fileName)
         return false;
     QTextStream stream(&file);
     for (const QString& s:list) {
-        stream<<s
-#if QT_VERSION >= QT_VERSION_CHECK(5,15,0)
-             <<Qt::endl;
-#else
-             <<endl;
-#endif
+        stream<<s<<Qt::endl;
     }
     return true;
 }
diff --git a/libs/redpanda_qt_utils/redpanda_qt_utils.pro b/libs/redpanda_qt_utils/redpanda_qt_utils.pro
index 76171735..f63e244b 100644
--- a/libs/redpanda_qt_utils/redpanda_qt_utils.pro
+++ b/libs/redpanda_qt_utils/redpanda_qt_utils.pro
@@ -3,8 +3,7 @@ QT += core gui
 
 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
-# without `c++14` old versions of qmake will explicitly set `-std=gnu++98`
-CONFIG += c++14 c++17
+CONFIG += c++17
 CONFIG += nokey
 CONFIG += staticlib