diff --git a/wquery/context.py b/wquery/context.py
index 4ea1b54..ee7b796 100644
--- a/wquery/context.py
+++ b/wquery/context.py
@@ -28,7 +28,7 @@
 from .lang import _
 from .odds import get_model_byId, get_ord_from_fldname
 
-VERSION = '20170416001'
+VERSION = 'V4.0.20170506'
 CONFIG_FILENAME = '.wqcfg'
 
 
diff --git a/wquery/lang.py b/wquery/lang.py
index 3ed60f3..ac3978f 100644
--- a/wquery/lang.py
+++ b/wquery/lang.py
@@ -37,13 +37,23 @@
     'DICT_FIELDS': {'zh_CN': u'<b>字典字段</b>', 'en': u'<b>Dict fields</b>', 'fr': u'<b>Champ de dico</b>'},
     'RADIOS_DESC': {'zh_CN': u'<b>单选框选中为待查询单词字段</b>', 'en': u'<b>Word field needs to be selected.</b>', 'fr': u'<b>Champ de mot doit d\'être sélectionné. </b>'},
     'NO_QUERY_WORD': {'zh_CN': u'查询字段无单词', 'en': u'No word is found in the query field', 'fr': u'Aucun est trouvé dans le champ'},
-    'CSS_NOT_FOUND': {'zh_CN': u'没有找到CSS文件，请手动选择', 'en': u'No valid css stylesheets found, please choose the file', 'fr': u'Aucun fichier de style CSS valide, veuillez choisir le fichier'}
+    'CSS_NOT_FOUND': {'zh_CN': u'没有找到CSS文件，请手动选择', 'en': u'No valid css stylesheets found, please choose the file', 'fr': u'Aucun fichier de style CSS valide, veuillez choisir le fichier'},
+    'ABOUT': {'zh_CN': u'关于'},
+    'REPOSITORY': {'zh_CN': u'项目地址'},
+    'FEEDBACK': {'zh_CN': u'反馈'},
+    'VERSION': {'zh_CN': u'版本'}
 }
 
 
 def _(key, lang=currentLang):
     if lang != 'zh_CN' and lang != 'en' and lang != 'fr':
         lang = 'en'  # fallback
+
+    def disp(s):
+        return '{first_character}{others}'.format(first_character=s[0].upper(), others=s[1:].lower())
+
+    if not trans.has_key(key) or not trans[key].has_key(lang):
+        return disp(key)
     return trans[key][lang]
 
 
diff --git a/wquery/ui.py b/wquery/ui.py
index 6e4bbe0..f7b4de7 100644
--- a/wquery/ui.py
+++ b/wquery/ui.py
@@ -28,7 +28,7 @@
 from aqt.studydeck import StudyDeck
 from aqt.utils import shortcut, showInfo
 
-from .context import config
+from .context import config, VERSION
 from .lang import _, _sl
 from .odds import get_model_byId, get_ord_from_fldname
 from .service import service_manager
@@ -140,8 +140,11 @@ def build(self):
         self.main_layout.addWidget(scroll_area)
         # add description of radio buttons AND ok button
         bottom_layout = QHBoxLayout()
+        about_btn = QPushButton(_('ABOUT'))
+        about_btn.clicked.connect(self.show_about)
         btnbox = QDialogButtonBox(QDialogButtonBox.Ok, Qt.Horizontal, self)
         btnbox.accepted.connect(self.accept)
+        bottom_layout.addWidget(about_btn)
         bottom_layout.addWidget(QLabel(_("RADIOS_DESC")))
         bottom_layout.addWidget(btnbox)
         self.main_layout.addLayout(bottom_layout)
@@ -156,6 +159,13 @@ def build(self):
                 # build fields -- dicts layout
                 self.build_mappings_layout(model)
 
+    def show_about(self):
+        info = u'<b>{t0}</b><br />{version}<br /><b>{t1}</b><br /><a href="{url}">{url}</a><br /><b>{t2}</b><br /><a href="{feedback0}">{feedback0}</a><br /><a href="mailto:{feedback1}">{feedback1}</a>'.format(
+            t0=_('VERSION'), version=VERSION,
+            t1=_('REPOSITORY'), url=u'https://github.com/finalion/WordQuery',
+            t2=_('FEEDBACK'), feedback0=u'https://github.com/finalion/WordQuery/issues', feedback1=u'finalion@gmail.com')
+        QMessageBox.about(self, _('ABOUT'), info)
+
     def show_fm_dialog(self):
         fm_dialog = FoldersManageDialog(self)
         fm_dialog.activateWindow()
@@ -302,12 +312,12 @@ def add_dict_layout(self, i, **kwargs):
         kwargs:
         word_checked  dict  fld_name dict_field
         """
-        word_checked, dict_name, dict_unique, fld_name, dict_field =\
-            kwargs.get('word_checked', False), \
-            kwargs.get('dict', _('NOT_DICT_FIELD')), \
-            kwargs.get('dict_unique', ''),\
-            kwargs.get('fld_name', ''), \
-            kwargs.get('dict_field', '')
+        word_checked, dict_name, dict_unique, fld_name, dict_field = (
+            kwargs.get('word_checked', False),
+            kwargs.get('dict', _('NOT_DICT_FIELD')),
+            kwargs.get('dict_unique', ''),
+            kwargs.get('fld_name', ''),
+            kwargs.get('dict_field', ''),)
 
         fldname_label = QRadioButton(fld_name)
         fldname_label.setMinimumSize(100, 0)