diff --git a/README.rst b/README.rst
index 660846b..1d4a855 100644
--- a/README.rst
+++ b/README.rst
@@ -151,8 +151,8 @@ The CKAN harvesters support a number of configuration options to control their
 behaviour. Those need to be defined as a JSON object in the configuration form
 field. The currently supported configuration options are:
 
-*   api_version: You can force the harvester to use either version '1' or '2' of
-    the CKAN API. Default is '2'.
+*   api_version: You can force the harvester to use either version 1 or 2 of
+    the CKAN API. Default is 2.
 
 *   default_tags: A list of tags that will be added to all harvested datasets.
     Tags don't need to previously exist.
@@ -160,7 +160,7 @@ field. The currently supported configuration options are:
 *   default_groups: A list of groups to which the harvested datasets will be
     added to. The groups must exist. Note that you must use ids or names to
     define the groups according to the API version you defined (names for version
-    '1', ids for version '2').
+    1, ids for version 2).
 
 *   default_extras: A dictionary of key value pairs that will be added to extras
     of the harvested datasets. You can use the following replacement strings,
@@ -204,7 +204,7 @@ Here is an example of a configuration object (the one that must be entered in
 the configuration field)::
 
     {
-     "api_version":"1",
+     "api_version": 1,
      "default_tags":["new-tag-1","new-tag-2"],
      "default_groups":["my-own-group"],
      "default_extras":{"new_extra":"Test","harvest_url":"{harvest_source_url}/dataset/{dataset_id}"},
diff --git a/ckanext/harvest/harvesters/base.py b/ckanext/harvest/harvesters/base.py
index 9a6a9df..06801c6 100644
--- a/ckanext/harvest/harvesters/base.py
+++ b/ckanext/harvest/harvesters/base.py
@@ -130,11 +130,15 @@ class HarvesterBase(SingletonPlugin):
 
             # Check API version
             if self.config:
-                api_version = self.config.get('api_version','2')
+                try:
+                    api_version = int(self.config.get('api_version', 2))
+                except ValueError:
+                    raise ValueError('api_version must be an integer')
+
                 #TODO: use site user when available
-                user_name = self.config.get('user',u'harvest')
+                user_name = self.config.get('user', u'harvest')
             else:
-                api_version = '2'
+                api_version = 2
                 user_name = u'harvest'
 
             context = {
diff --git a/ckanext/harvest/harvesters/ckanharvester.py b/ckanext/harvest/harvesters/ckanharvester.py
index 981864d..df99cad 100644
--- a/ckanext/harvest/harvesters/ckanharvester.py
+++ b/ckanext/harvest/harvesters/ckanharvester.py
@@ -20,13 +20,13 @@ class CKANHarvester(HarvesterBase):
     '''
     config = None
 
-    api_version = '2'
+    api_version = 2
 
     def _get_rest_api_offset(self):
-        return '/api/%s/rest' % self.api_version
+        return '/api/%d/rest' % self.api_version
 
     def _get_search_api_offset(self):
-        return '/api/%s/search' % self.api_version
+        return '/api/%d/search' % self.api_version
 
     def _get_content(self, url):
         http_request = urllib2.Request(
@@ -53,7 +53,10 @@ class CKANHarvester(HarvesterBase):
             self.config = json.loads(config_str)
 
             if 'api_version' in self.config:
-                self.api_version = self.config['api_version']
+                try:
+                    self.api_version = int(self.config['api_version'])
+                except ValueError:
+                    raise ValueError('api_version must be an integer')
 
             log.debug('Using config: %r', self.config)
         else:
@@ -263,7 +266,7 @@ class CKANHarvester(HarvesterBase):
                     try:
                         data_dict = {'id': group_name}
                         group = get_action('group_show')(context, data_dict)
-                        if self.api_version == '1':
+                        if self.api_version == 1:
                             validated_groups.append(group['name'])
                         else:
                             validated_groups.append(group['id'])
@@ -280,7 +283,7 @@ class CKANHarvester(HarvesterBase):
                                 group.pop(key, None)
                             get_action('group_create')(context, group)
                             log.info('Group %s has been newly created' % group_name)
-                            if self.api_version == '1':
+                            if self.api_version == 1:
                                 validated_groups.append(group['name'])
                             else:
                                 validated_groups.append(group['id'])