diff --git a/src/configuredialog/configagentdelegate.cpp b/src/configuredialog/configagentdelegate.cpp
index 980667cf3..0307cefef 100644
--- a/src/configuredialog/configagentdelegate.cpp
+++ b/src/configuredialog/configagentdelegate.cpp
@@ -36,8 +36,8 @@ struct Icons {
     {
     }
 
-    QPixmap readyPixmap, syncPixmap, errorPixmap, offlinePixmap;
-    QIcon checkMailIcon;
+    const QPixmap readyPixmap, syncPixmap, errorPixmap, offlinePixmap;
+    const QIcon checkMailIcon;
 };
 
 Q_GLOBAL_STATIC(Icons, s_icons)
diff --git a/src/dialog/archivefolderdialog.cpp b/src/dialog/archivefolderdialog.cpp
index 986752272..35f668e3a 100644
--- a/src/dialog/archivefolderdialog.cpp
+++ b/src/dialog/archivefolderdialog.cpp
@@ -36,7 +36,7 @@ using namespace MailCommon;
 QString ArchiveFolderDialog::standardArchivePath(const QString &folderName)
 {
     QString currentPath = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
-    QDir dir(currentPath);
+    const QDir dir(currentPath);
     if (!dir.exists()) {
         currentPath = QDir::homePath();
     }
diff --git a/src/editor/kmcomposerwin.h b/src/editor/kmcomposerwin.h
index 3009b5fae..754069fd3 100644
--- a/src/editor/kmcomposerwin.h
+++ b/src/editor/kmcomposerwin.h
@@ -561,8 +561,8 @@ private:
 
     KMime::Message::Ptr mMsg;
     QGridLayout *mGrid = nullptr;
-    QString mTextSelection;
-    QString mCustomTemplate;
+    const QString mTextSelection;
+    const QString mCustomTemplate;
     bool mLastSignActionState = false;
     bool mLastEncryptActionState = false;
     bool mSigningAndEncryptionExplicitlyDisabled = false;
@@ -576,7 +576,7 @@ private:
     QFont mBodyFont;
     QFont mFixedFont;
     uint mId = 0;
-    TemplateContext mContext = NoTemplate;
+    const TemplateContext mContext = NoTemplate;
 
     KRecentFilesAction *mRecentAction = nullptr;
 
diff --git a/src/folderarchive/folderarchiveagentcheckcollection.h b/src/folderarchive/folderarchiveagentcheckcollection.h
index 0af03c0cb..e876c9184 100644
--- a/src/folderarchive/folderarchiveagentcheckcollection.h
+++ b/src/folderarchive/folderarchiveagentcheckcollection.h
@@ -28,7 +28,7 @@ private:
     void slotInitialCollectionFetchingFirstLevelDone(KJob *job);
     void slotCreateNewFolder(KJob *);
     void createNewFolder(const QString &name);
-    QDate mCurrentDate;
+    const QDate mCurrentDate;
     FolderArchiveAccountInfo *const mInfo;
 };
 
diff --git a/src/folderarchive/folderarchiveagentjob.h b/src/folderarchive/folderarchiveagentjob.h
index ce5b5bed2..8006eb394 100644
--- a/src/folderarchive/folderarchiveagentjob.h
+++ b/src/folderarchive/folderarchiveagentjob.h
@@ -30,7 +30,7 @@ private:
     void slotMoveMessages(KMMoveCommand *);
 
     void sendError(const QString &error);
-    Akonadi::Item::List mListItem;
+    const Akonadi::Item::List mListItem;
     FolderArchiveManager *const mManager;
     FolderArchiveAccountInfo *const mInfo;
 };
diff --git a/src/foldershortcutactionmanager.h b/src/foldershortcutactionmanager.h
index 2b5a31d1d..f16c68aca 100644
--- a/src/foldershortcutactionmanager.h
+++ b/src/foldershortcutactionmanager.h
@@ -38,7 +38,7 @@ Q_SIGNALS:
 
 private:
     Q_DISABLE_COPY(FolderShortcutCommand)
-    Akonadi::Collection mCollectionFolder;
+    const Akonadi::Collection mCollectionFolder;
     QWidget *const mMainWidget;
     QAction *mAction = nullptr;
 };
diff --git a/src/job/addressvalidationjob.h b/src/job/addressvalidationjob.h
index 867ad0079..b95b3be05 100644
--- a/src/job/addressvalidationjob.h
+++ b/src/job/addressvalidationjob.h
@@ -29,7 +29,7 @@ public:
 
 private:
     void slotAliasExpansionDone(KJob *);
-    QString mEmailAddresses;
+    const QString mEmailAddresses;
     QString mDomainDefaultName;
     bool mIsValid = false;
     QWidget *const mParentWidget;
diff --git a/src/job/createtaskjob.h b/src/job/createtaskjob.h
index 836a62a02..93570cdb7 100644
--- a/src/job/createtaskjob.h
+++ b/src/job/createtaskjob.h
@@ -25,7 +25,7 @@ private:
     void slotModifyItemDone(KJob *job);
 
     void fetchItems();
-    Akonadi::Item::List mListItem;
+    const Akonadi::Item::List mListItem;
 };
 
 #endif // CREATETASKJOB_H
diff --git a/src/job/savedraftjob.h b/src/job/savedraftjob.h
index a0893dac4..dc2fb7c35 100644
--- a/src/job/savedraftjob.h
+++ b/src/job/savedraftjob.h
@@ -24,7 +24,7 @@ public:
 private:
     void slotStoreDone(KJob *job);
     KMime::Message::Ptr mMsg = nullptr;
-    Akonadi::Collection mCollection;
+    const Akonadi::Collection mCollection;
 };
 
 #endif // SAVEDRAFTJOB_H