diff --git a/isogeo.py b/isogeo.py
index fdd7394b..7c6bedb4 100644
--- a/isogeo.py
+++ b/isogeo.py
@@ -31,19 +31,19 @@
 import platform  # about operating systems
 from collections import OrderedDict
 from functools import partial
+import operator
 
 # PyQT
 # from QByteArray
-from PyQt5.QtCore import (QByteArray, QCoreApplication, QSettings,
+from PyQt4.QtCore import (QByteArray, QCoreApplication, QSettings,
                           Qt, QTranslator, QUrl, qVersion)
-from PyQt5.QtGui import (QIcon, QMessageBox, QStandardItemModel,
+from PyQt4.QtGui import (QAction, QIcon, QMessageBox, QStandardItemModel,
                          QStandardItem, QProgressBar)
-from PyQt5.QtNetwork import QNetworkAccessManager, QNetworkRequest
-from PyQt5.QtWidgets import QAction
+from PyQt4.QtNetwork import QNetworkAccessManager, QNetworkRequest
 
 # PyQGIS
 import db_manager.db_plugins.postgis.connector as con
-from qgis.utils import iface, plugin_times, QGis
+from qgis.utils import iface, plugin_times, QGis, reloadPlugin
 from qgis.core import (QgsAuthManager, QgsAuthMethodConfig,
                        QgsCoordinateReferenceSystem, QgsCoordinateTransform,
                        QgsDataSourceURI,
@@ -52,7 +52,7 @@
                        QgsPoint, QgsRectangle, QgsRasterLayer, QgsVectorLayer)
 
 # Initialize Qt resources from file resources.py
-# import resources
+import resources
 
 # UI classes
 from ui.isogeo_dockwidget import IsogeoDockWidget  # main widget
diff --git a/modules/api.py b/modules/api.py
index 05def465..c44539cb 100644
--- a/modules/api.py
+++ b/modules/api.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import (absolute_import, print_function, unicode_literals)
 # Standard library
 import base64
 import json
@@ -8,9 +8,9 @@
 from urllib import urlencode
 
 # PyQT
-from PyQt5.QtCore import QByteArray, QSettings, QUrl
-from PyQt5.QtGui import QMessageBox
-from PyQt5.QtNetwork import QNetworkRequest
+from PyQt4.QtCore import QByteArray, QSettings, QUrl
+from PyQt4.QtGui import QMessageBox
+from PyQt4.QtNetwork import QNetworkRequest
 
 # PyQGIS
 from qgis.core import QgsMessageLog
diff --git a/modules/metadata_display.py b/modules/metadata_display.py
index 42edc0e4..c195e887 100644
--- a/modules/metadata_display.py
+++ b/modules/metadata_display.py
@@ -1,4 +1,6 @@
 # -*- coding: utf-8 -*-
+from __future__ import (absolute_import, division, print_function, unicode_literals)
+
 # Standard library
 import logging
 from datetime import datetime
@@ -10,8 +12,8 @@
 from qgis.gui import QgsMapCanvasLayer
 
 # PyQT
-from PyQt5.QtCore import QSettings, Qt
-from PyQt5.QtGui import QTableWidgetItem
+from PyQt4.QtCore import QSettings, Qt
+from PyQt4.QtGui import QTableWidgetItem
 
 # Custom modules
 from .api import IsogeoApiManager
diff --git a/modules/tools.py b/modules/tools.py
index c7bbe744..e5ea8201 100644
--- a/modules/tools.py
+++ b/modules/tools.py
@@ -3,6 +3,7 @@
 # Standard library
 import datetime
 import logging
+from functools import partial
 from os import path
 from urllib import getproxies, unquote, urlencode
 import webbrowser
@@ -13,8 +14,8 @@
 from qgis.utils import iface
 
 # PyQT
-from PyQt5.QtCore import QSettings, QUrl
-from PyQt5.QtGui import QMessageBox
+from PyQt4.QtCore import QSettings, QUrl
+from PyQt4.QtGui import QMessageBox
 
 # ############################################################################
 # ########## Globals ###############
diff --git a/modules/url_builder.py b/modules/url_builder.py
index d0dd88fc..8543f46d 100644
--- a/modules/url_builder.py
+++ b/modules/url_builder.py
@@ -1,15 +1,20 @@
 # -*- coding: utf-8 -*-
+from __future__ import (absolute_import, division, print_function, unicode_literals)
 
 # Standard library
+from datetime import datetime
 import logging
 import re
 from urllib import unquote, urlencode
+from urlparse import urlparse
 
 # PyQT
-from PyQt5.QtCore import QSettings
+from PyQt4.QtCore import QSettings, QUrl
+from PyQt4.QtNetwork import QNetworkAccessManager, QNetworkRequest
 
 # QGIS
-from qgis.core import QgsDataSourceURI
+from qgis.core import (QgsDataSourceURI, QgsNetworkAccessManager,
+                       QgsVectorLayer, QgsMapLayerRegistry, QgsRasterLayer)
 
 # Custom modules
 from .tools import Tools