Starting on Version 7.0 using the work done by others. Completely untested. I will be testing things, but I thought I'd get this base version up for others to give pull requests.

THIS IS ON THE MASTER BRANCH. The Master branch will be Python 3.0 from now on. While Python 2.7 support will not be deliberately broken, all efforts should now focus on Python 3.0 compatibility.

I can see a lot of work has been done. There's more to do. I've bumped the version number of everything I came across to the next major number for Python 3.0 compatibility indication.

Thanks everyone. I hope to update here at least once a week until we have a stable 7.0 release for calibre 5.0

Obok_plugin/config.py

@@ -75,7 +75,7 @@ class ConfigWidget(QWidget):
 
 
     def save_settings(self):
-        plugin_prefs['finding_homes_for_formats'] = unicode(self.find_homes.currentText())
+        plugin_prefs['finding_homes_for_formats'] = self.find_homes.currentText()
         plugin_prefs['kobo_serials'] = self.tmpserials
         plugin_prefs['kobo_directory'] = self.kobodirectory
 
@@ -165,7 +165,7 @@ class ManageKeysDialog(QDialog):
     def delete_key(self):
         if not self.listy.currentItem():
             return
-        keyname = unicode(self.listy.currentItem().text())
+        keyname = self.listy.currentItem().text()
         if not question_dialog(self, "{0} {1}: Confirm Delete".format(PLUGIN_NAME, PLUGIN_VERSION), u"Do you really want to delete the {1} <strong>{0}</strong>?".format(keyname, self.key_type_name), show_copy_button=False, default_yes=False):
             return
         self.plugin_keys.remove(keyname)
@@ -202,11 +202,11 @@ class AddSerialDialog(QDialog):
 
     @property
     def key_name(self):
-        return unicode(self.key_ledit.text()).strip()
+        return self.key_ledit.text().strip()
 
     @property
     def key_value(self):
-        return unicode(self.key_ledit.text()).strip()
+        return self.key_ledit.text().strip()
 
     def accept(self):
         if len(self.key_name) == 0 or self.key_name.isspace():