diff --git a/python_semrush/semrush.py b/python_semrush/semrush.py
index 0a87ef9..e0e7000 100644
--- a/python_semrush/semrush.py
+++ b/python_semrush/semrush.py
@@ -916,3 +916,8 @@ def backlinks_pages(self, target, target_type='root_domain', **kwargs):
         """
         self.api_url = SEMRUSH_API_V1_URL
         return self.produce('backlinks_pages', target=target, target_type=target_type, **kwargs)
+
+    def subfolder_rank_history(self, domain, database, **kwargs):
+        if database not in REGIONAL_DATABASES.values():
+            raise SemRushRegionalDatabaseError('%s - is not an accepted database.' % database)
+        return self.produce('subfolder_rank_history', domain=domain, database=database, **kwargs)
diff --git a/requirements.txt b/requirements.txt
index 1a67437..761c161 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-requests==2.8.1
\ No newline at end of file
+requests==2.18
diff --git a/requirements/default.txt b/requirements/default.txt
index 1a67437..761c161 100644
--- a/requirements/default.txt
+++ b/requirements/default.txt
@@ -1 +1 @@
-requests==2.8.1
\ No newline at end of file
+requests==2.18