diff --git a/sources/queued/QueuedConfig.h.in b/sources/queued/QueuedConfig.h.in
index 9c11ce4..6f2ae23 100644
--- a/sources/queued/QueuedConfig.h.in
+++ b/sources/queued/QueuedConfig.h.in
@@ -85,6 +85,13 @@ const char LIB_INSTALL_DIR[] = "@LIB_INSTALL_DIR@";
  */
 const char ROOT_INSTALL_DIR[] = "@CMAKE_INSTALL_PREFIX@";
 
+// internal configuration
+/**
+ * @ingroup QueuedConfig
+ * @brief version of internal storage
+ */
+const int DATABASE_VERSION = 1;
+
 // plugin interfaces
 /**
  * @brief plugin interface name
diff --git a/sources/queued/include/queued/QueuedAdvancedSettings.h b/sources/queued/include/queued/QueuedAdvancedSettings.h
index b19a605..58668d5 100644
--- a/sources/queued/include/queued/QueuedAdvancedSettings.h
+++ b/sources/queued/include/queued/QueuedAdvancedSettings.h
@@ -48,6 +48,11 @@ public:
      * @brief QueuedAdvancedSettings class destructor
      */
     virtual ~QueuedAdvancedSettings();
+    /**
+     * @brief check database version
+     * @return true if no version update required, otherwise return false
+     */
+    bool checkDatabaseVersion() const;
     /**
      * @brief get value
      * @param _key
@@ -76,6 +81,13 @@ public:
      * @return ID in settings representation
      */
     static QString internalId(const QString &_key);
+    /**
+     * @brief get internal ID by given string key
+     * @param _key
+     * string key
+     * @return ID in settings representation
+     */
+    static QString internalId(const QueuedCfg::QueuedSettings _key);
     /**
      * @brief set value
      * @param _key
diff --git a/sources/queued/include/queued/QueuedConfiguration.h b/sources/queued/include/queued/QueuedConfiguration.h
index ed9e328..02e9163 100644
--- a/sources/queued/include/queued/QueuedConfiguration.h
+++ b/sources/queued/include/queued/QueuedConfiguration.h
@@ -28,6 +28,8 @@
 #include <QString>
 #include <QVariant>
 
+#include "QueuedConfig.h"
+
 
 /**
  * @defgroup QueuedCfg
@@ -91,6 +93,8 @@ typedef struct {
  * on queued exit action enum
  * @var Settings::TokenExpiration
  * token expiration value in days
+ * @var Settings::DatabaseVersion
+ * internal field to control current database version
  */
 enum class QueuedSettings {
     Invalid = 1 << 0,
@@ -100,6 +104,7 @@ enum class QueuedSettings {
     KeepUsers = 1 << 4,
     OnExitAction = 1 << 5,
     TokenExpiration = 1 << 6,
+    DatabaseVersion = 1 << 7
 };
 /**
  * @ingroup QueuedCfg
@@ -133,7 +138,9 @@ const QueuedSettingsDefaultMap QueuedSettingsDefaults = {
     {"KeepTasks", {QueuedSettings::KeepTasks, 0}},
     {"KeepUsers", {QueuedSettings::KeepUsers, 0}},
     {"OnExitAction", {QueuedSettings::OnExitAction, 2}},
-    {"TokenExpiration", {QueuedSettings::TokenExpiration, 39}}};
+    {"TokenExpiration", {QueuedSettings::TokenExpiration, 30}},
+    {"DatabaseVersion",
+     {QueuedSettings::DatabaseVersion, QueuedConfig::DATABASE_VERSION}}};
 };
 
 #endif /* QUEUEDCONFIGURATION_H */
diff --git a/sources/queued/include/queued/QueuedCore.h b/sources/queued/include/queued/QueuedCore.h
index 407fa6e..f194eff 100644
--- a/sources/queued/include/queued/QueuedCore.h
+++ b/sources/queued/include/queued/QueuedCore.h
@@ -317,6 +317,88 @@ private:
      * @brief init users
      */
     void initUsers();
+    // private interfaces
+    /**
+     * @brief add new task
+     * @param _command
+     * command line
+     * @param _arguments
+     * command arguments
+     * @param _workingDirectory
+     * working directory
+     * @param _nice
+     * nice level
+     * @param _userId
+     * task owner user ID
+     * @param _limits
+     * task defined limits
+     * @return true on successfully addition
+     */
+    bool addTaskPrivate(const QString &_command, const QStringList &_arguments,
+                        const QString &_workingDirectory, const uint _nice,
+                        const long long _userId,
+                        const QueuedLimits::Limits &_limits);
+    /**
+     * @brief add new user
+     * @param _name
+     * user name
+     * @param _email
+     * user email
+     * @param _password
+     * user password
+     * @param _permissions
+     * user permissions
+     * @param _limits
+     * user limits
+     * @return true on successfully addition
+     */
+    bool addUserPrivate(const QString &_name, const QString &_email,
+                        const QString &_password, const uint _permissions,
+                        const QueuedLimits::Limits &_limits);
+    /**
+     * @brief edit advanced settings
+     * @param _key
+     * advanced settings key
+     * @param _value
+     * advanced settings value
+     * @return true on successful option edition
+     */
+    bool editOptionPrivate(const QString &_key, const QVariant &_value);
+    /**
+     * @brief edit task
+     * @param _id
+     * task ID to edit
+     * @param _taskData
+     * task data to edit
+     * @remark _taskData should contain only fields defined in schema, any other
+     * fields will be ignored. No need to pass all properties here
+     * @return true on successful task edition
+     */
+    bool editTaskPrivate(const long long _id, const QVariantHash &_taskData);
+    /**
+     * @brief edit user
+     * @param _id
+     * user ID to edit
+     * @param _userData
+     * user data to edit
+     * @remark _userData should contain only fields defined in schema, any other
+     * fields will be ignored. No need to pass all properties here
+     * @return true on successful user edition
+     */
+    bool editUserPrivate(const long long _id, const QVariantHash &_userData);
+    /**
+     * @brief edit user permissions
+     * @param _id
+     * user ID to edit
+     * @param _permission
+     * permission to add or remove
+     * @param _add
+     * indicates whether it should be added or removed
+     * @return true on successful user permission edition
+     */
+    bool editUserPermissionPrivate(const long long _id,
+                                   const QueuedEnums::Permission &_permission,
+                                   const bool _add);
 };
 
 
diff --git a/sources/queued/src/QueuedAdvancedSettings.cpp b/sources/queued/src/QueuedAdvancedSettings.cpp
index ce9d559..5261072 100644
--- a/sources/queued/src/QueuedAdvancedSettings.cpp
+++ b/sources/queued/src/QueuedAdvancedSettings.cpp
@@ -47,6 +47,20 @@ QueuedAdvancedSettings::~QueuedAdvancedSettings()
 }
 
 
+/**
+ * @fn checkDatabase
+ */
+bool QueuedAdvancedSettings::checkDatabaseVersion() const
+{
+    QString key = internalId(QueuedCfg::QueuedSettings::DatabaseVersion);
+
+    if (m_values.contains(key.toLower()))
+        return get(key).toInt() == QueuedConfig::DATABASE_VERSION;
+    else
+        return false;
+}
+
+
 /**
  * @fn get
  */
@@ -108,6 +122,23 @@ QString QueuedAdvancedSettings::internalId(const QString &_key)
 }
 
 
+/**
+ * @fn internalId
+ */
+QString QueuedAdvancedSettings::internalId(const QueuedCfg::QueuedSettings _key)
+{
+    qCDebug(LOG_LIB) << "Looking for key" << static_cast<int>(_key);
+
+    for (auto &internal : QueuedCfg::QueuedSettingsDefaults.keys()) {
+        if (QueuedCfg::QueuedSettingsDefaults[internal].id != _key)
+            continue;
+        return internal;
+    }
+
+    return QString();
+}
+
+
 /**
  * @fn set
  */
diff --git a/sources/queued/src/QueuedCore.cpp b/sources/queued/src/QueuedCore.cpp
index ff3c911..6f3df37 100644
--- a/sources/queued/src/QueuedCore.cpp
+++ b/sources/queued/src/QueuedCore.cpp
@@ -92,35 +92,8 @@ bool QueuedCore::addTask(
         }
     }
 
-    // add to database
-    auto ids = m_users->ids(_userId);
-    auto user = m_users->user(_userId);
-    if (!user) {
-        qCWarning(LOG_LIB) << "Could not find task user" << _userId;
-        return false;
-    }
-    auto taskLimits = QueuedLimits::minimalLimits(
-        _limits, user->nativeLimits(),
-        QueuedLimits::Limits(
-            m_advancedSettings->get(QueuedCfg::QueuedSettings::DefaultLimits)
-                .toString()));
-    QVariantHash properties = {{"user", _userId},
-                               {"command", _command},
-                               {"commandArguments", _arguments},
-                               {"workDirectory", _workingDirectory},
-                               {"nice", _nice},
-                               {"uid", ids.first},
-                               {"gid", ids.second},
-                               {"limits", taskLimits.toString()}};
-    auto id = m_database->add(QueuedDB::TASKS_TABLE, properties);
-    if (id == -1) {
-        qCWarning(LOG_LIB) << "Could not add task" << _command;
-        return false;
-    }
-
-    // add to child object
-    m_processes->add(properties, id);
-    return true;
+    return addTaskPrivate(_command, _arguments, _workingDirectory, _nice,
+                          _userId, _limits);
 }
 
 
@@ -149,25 +122,13 @@ bool QueuedCore::addUser(
         return false;
     }
 
-    // add to dababase
-    QVariantHash properties
-        = {{"name", _name},
-           {"password", QueuedUser::hashFromPassword(_password)},
-           {"email", _email},
-           {"permissions", _permissions},
-           {"limits", _limits.toString()}};
-    auto id = m_database->add(QueuedDB::USERS_TABLE, properties);
-    if (id == -1) {
-        qCWarning(LOG_LIB) << "Could not add user" << _name;
-        return false;
-    }
-
-    // add to child object
-    m_users->add(properties, id);
-    return true;
+    return addUserPrivate(_name, _email, _password, _permissions, _limits);
 }
 
 
+/**
+ * @fn authorization
+ */
 QueuedUserManager::QueuedUserAuthorization
 QueuedCore::authorization(const QString &_name, const QString &_password)
 {
@@ -206,25 +167,7 @@ bool QueuedCore::editOption(
         return false;
     }
 
-    // add to database
-    long long id = m_advancedSettings->id(_key);
-    QVariantHash payload = {{"key", _key}, {"value", _value}};
-
-    bool status = false;
-    if (id == -1) {
-        id = m_database->add(QueuedDB::SETTINGS_TABLE, payload);
-        qCInfo(LOG_LIB) << "Added new key with ID" << id;
-        status = (id != -1);
-    } else {
-        status = m_database->modify(QueuedDB::SETTINGS_TABLE, id, payload);
-        qCInfo(LOG_LIB) << "Value for" << _key
-                        << "has been modified with status" << status;
-    }
-
-    // add to child objectm
-    if (status)
-        m_advancedSettings->set(_key, _value);
-    return status;
+    return editOptionPrivate(_key, _value);
 }
 
 
@@ -281,20 +224,7 @@ bool QueuedCore::editTask(
         = isAdmin ? _taskData
                   : dropAdminFields(QueuedDB::TASKS_TABLE, _taskData);
 
-    // modify record in database first
-    bool status = m_database->modify(QueuedDB::TASKS_TABLE, _id, payload);
-    if (!status) {
-        qCWarning(LOG_LIB) << "Could not modify task record" << _id
-                           << "in database, do not edit it in memory";
-        return false;
-    }
-
-    // modify values stored in memory
-    for (auto &property : payload.keys())
-        task->setProperty(property.toLocal8Bit().constData(),
-                          payload[property]);
-
-    return true;
+    return editTaskPrivate(_id, payload);
 }
 
 
@@ -334,20 +264,7 @@ bool QueuedCore::editUser(
         = isAdmin ? _userData
                   : dropAdminFields(QueuedDB::USERS_TABLE, _userData);
 
-    // modify record in database first
-    bool status = m_database->modify(QueuedDB::USERS_TABLE, _id, payload);
-    if (!status) {
-        qCWarning(LOG_LIB) << "Could not modify user record" << _id
-                           << "in database, do not edit it in memory";
-        return false;
-    }
-
-    // modify values stored in memory
-    for (auto &property : payload.keys())
-        user->setProperty(property.toLocal8Bit().constData(),
-                          payload[property]);
-
-    return true;
+    return editUserPrivate(_id, payload);
 }
 
 
@@ -361,12 +278,6 @@ bool QueuedCore::editUserPermission(
     qCDebug(LOG_LIB) << "Edit permissions" << static_cast<int>(_permission)
                      << "for user" << _id << "add" << _add;
 
-    auto user = m_users->user(_id);
-    if (!user) {
-        qCWarning(LOG_LIB) << "Could not find user with ID" << _id;
-        return false;
-    }
-
     // check permissions
     auto authUser = m_users->user(_auth.user);
     if (!authUser) {
@@ -383,29 +294,7 @@ bool QueuedCore::editUserPermission(
         }
     }
 
-    // edit runtime permissions to get value
-    if (_add)
-        user->addPermissions(_permission);
-    else
-        user->removePermissions(_permission);
-    uint permissions = user->permissions();
-    qCInfo(LOG_LIB) << "New user permissions";
-
-    // modify in database now
-    QVariantHash payload = {{"permissions", permissions}};
-    bool status = m_database->modify(QueuedDB::USERS_TABLE, _id, payload);
-    if (!status) {
-        qCWarning(LOG_LIB) << "Could not modify user record" << _id
-                           << "in database, do not edit it in memory";
-        // rollback in-memory values
-        if (_add)
-            user->removePermissions(_permission);
-        else
-            user->addPermissions(_permission);
-        return false;
-    }
-
-    return true;
+    return editUserPermissionPrivate(_id, _permission, _add);
 }
 
 
@@ -597,6 +486,8 @@ void QueuedCore::updateSettings(const QueuedCfg::QueuedSettings _key,
     case QueuedCfg::QueuedSettings::DatabaseInterval:
         m_databaseManager->setInterval(_value.toLongLong());
         break;
+    case QueuedCfg::QueuedSettings::DatabaseVersion:
+        break;
     case QueuedCfg::QueuedSettings::DefaultLimits:
         break;
     case QueuedCfg::QueuedSettings::KeepTasks:
@@ -762,6 +653,13 @@ void QueuedCore::initSettings(const QString &_configuration)
     // and load advanced settings
     m_advancedSettings = new QueuedAdvancedSettings(this);
     m_advancedSettings->set(m_database->get(QueuedDB::SETTINGS_TABLE));
+    if (!m_advancedSettings->checkDatabaseVersion()) {
+        qCInfo(LOG_LIB) << "Bump database version to"
+                        << QueuedConfig::DATABASE_VERSION;
+        editOptionPrivate(m_advancedSettings->internalId(
+                              QueuedCfg::QueuedSettings::DatabaseVersion),
+                          QueuedConfig::DATABASE_VERSION);
+    }
 
     // report manager
     m_reports = new QueuedReportManager(this, m_database);
@@ -794,3 +692,209 @@ void QueuedCore::initUsers()
         m_users, SIGNAL(userLoggedIn(const long long, const QDateTime &)), this,
         SLOT(updateUserLoginTime(const long long, const QDateTime &)));
 }
+
+
+/**
+ * @addTaskPrivate
+ */
+bool QueuedCore::addTaskPrivate(const QString &_command,
+                                const QStringList &_arguments,
+                                const QString &_workingDirectory,
+                                const uint _nice, const long long _userId,
+                                const QueuedLimits::Limits &_limits)
+{
+    qCDebug(LOG_LIB) << "Add task" << _command << "with arguments" << _arguments
+                     << "from user" << _userId;
+
+    // add to database
+    auto ids = m_users->ids(_userId);
+    auto user = m_users->user(_userId);
+    if (!user) {
+        qCWarning(LOG_LIB) << "Could not find task user" << _userId;
+        return false;
+    }
+    auto taskLimits = QueuedLimits::minimalLimits(
+        _limits, user->nativeLimits(),
+        QueuedLimits::Limits(
+            m_advancedSettings->get(QueuedCfg::QueuedSettings::DefaultLimits)
+                .toString()));
+    QVariantHash properties = {{"user", _userId},
+                               {"command", _command},
+                               {"commandArguments", _arguments},
+                               {"workDirectory", _workingDirectory},
+                               {"nice", _nice},
+                               {"uid", ids.first},
+                               {"gid", ids.second},
+                               {"limits", taskLimits.toString()}};
+    auto id = m_database->add(QueuedDB::TASKS_TABLE, properties);
+    if (id == -1) {
+        qCWarning(LOG_LIB) << "Could not add task" << _command;
+        return false;
+    }
+
+    // add to child object
+    m_processes->add(properties, id);
+    return true;
+}
+
+
+/**
+ * @fn addUserPrivate
+ */
+bool QueuedCore::addUserPrivate(const QString &_name, const QString &_email,
+                                const QString &_password,
+                                const uint _permissions,
+                                const QueuedLimits::Limits &_limits)
+{
+    qCDebug(LOG_LIB) << "Add user" << _name << "with email" << _email
+                     << "and permissions" << _permissions;
+    // add to database
+    QVariantHash properties
+        = {{"name", _name},
+           {"password", QueuedUser::hashFromPassword(_password)},
+           {"email", _email},
+           {"permissions", _permissions},
+           {"limits", _limits.toString()}};
+    auto id = m_database->add(QueuedDB::USERS_TABLE, properties);
+    if (id == -1) {
+        qCWarning(LOG_LIB) << "Could not add user" << _name;
+        return false;
+    }
+
+    // add to child object
+    m_users->add(properties, id);
+    return true;
+}
+
+
+/**
+ * @fn editOptionPrivate
+ */
+bool QueuedCore::editOptionPrivate(const QString &_key, const QVariant &_value)
+{
+    qCDebug(LOG_LIB) << "Set key" << _key << "to" << _value;
+
+    // add to database
+    long long id = m_advancedSettings->id(_key);
+    QVariantHash payload = {{"key", _key}, {"value", _value}};
+
+    bool status = false;
+    if (id == -1) {
+        id = m_database->add(QueuedDB::SETTINGS_TABLE, payload);
+        qCInfo(LOG_LIB) << "Added new key with ID" << id;
+        status = (id != -1);
+    } else {
+        status = m_database->modify(QueuedDB::SETTINGS_TABLE, id, payload);
+        qCInfo(LOG_LIB) << "Value for" << _key
+                        << "has been modified with status" << status;
+    }
+
+    // add to child object
+    if (status)
+        m_advancedSettings->set(_key, _value);
+    return status;
+}
+
+
+/**
+ * @fn editTaskPrivate
+ */
+bool QueuedCore::editTaskPrivate(const long long _id,
+                                 const QVariantHash &_taskData)
+{
+    qCDebug(LOG_LIB) << "Edit task with ID" << _id;
+
+    auto task = m_processes->process(_id);
+    if (!task) {
+        qCWarning(LOG_LIB) << "Could not find task with ID" << _id;
+        return false;
+    }
+
+    // modify record in database first
+    bool status = m_database->modify(QueuedDB::TASKS_TABLE, _id, _taskData);
+    if (!status) {
+        qCWarning(LOG_LIB) << "Could not modify task record" << _id
+                           << "in database, do not edit it in memory";
+        return false;
+    }
+
+    // modify values stored in memory
+    for (auto &property : _taskData.keys())
+        task->setProperty(property.toLocal8Bit().constData(),
+                          _taskData[property]);
+
+    return true;
+}
+
+
+/**
+ * @fn editUserPrivate
+ */
+bool QueuedCore::editUserPrivate(const long long _id,
+                                 const QVariantHash &_userData)
+{
+    qCDebug(LOG_LIB) << "Edit user with ID" << _id;
+
+    auto user = m_users->user(_id);
+    if (!user) {
+        qCWarning(LOG_LIB) << "Could not find user with ID" << _id;
+        return false;
+    };
+
+    // modify record in database first
+    bool status = m_database->modify(QueuedDB::USERS_TABLE, _id, _userData);
+    if (!status) {
+        qCWarning(LOG_LIB) << "Could not modify user record" << _id
+                           << "in database, do not edit it in memory";
+        return false;
+    }
+
+    // modify values stored in memory
+    for (auto &property : _userData.keys())
+        user->setProperty(property.toLocal8Bit().constData(),
+                          _userData[property]);
+
+    return true;
+}
+
+
+/**
+ * @fn editUserPermissionPrivate
+ */
+bool QueuedCore::editUserPermissionPrivate(
+    const long long _id, const QueuedEnums::Permission &_permission,
+    const bool _add)
+{
+    qCDebug(LOG_LIB) << "Edit permissions" << static_cast<int>(_permission)
+                     << "for user" << _id << "add" << _add;
+
+    auto user = m_users->user(_id);
+    if (!user) {
+        qCWarning(LOG_LIB) << "Could not find user with ID" << _id;
+        return false;
+    }
+
+    // edit runtime permissions to get value
+    if (_add)
+        user->addPermissions(_permission);
+    else
+        user->removePermissions(_permission);
+    uint permissions = user->permissions();
+    qCInfo(LOG_LIB) << "New user permissions";
+
+    // modify in database now
+    QVariantHash payload = {{"permissions", permissions}};
+    bool status = m_database->modify(QueuedDB::USERS_TABLE, _id, payload);
+    if (!status) {
+        qCWarning(LOG_LIB) << "Could not modify user record" << _id
+                           << "in database, do not edit it in memory";
+        // rollback in-memory values
+        if (_add)
+            user->removePermissions(_permission);
+        else
+            user->addPermissions(_permission);
+        return false;
+    }
+
+    return true;
+}