diff --git a/install_minimal/upgrades/airtime-1.9.0/airtimefilemonitor/mediamonitorcommon.py b/install_minimal/upgrades/airtime-1.9.0/airtimefilemonitor/mediamonitorcommon.py
index 9f0bcfd72..9d449c154 100644
--- a/install_minimal/upgrades/airtime-1.9.0/airtimefilemonitor/mediamonitorcommon.py
+++ b/install_minimal/upgrades/airtime-1.9.0/airtimefilemonitor/mediamonitorcommon.py
@@ -8,7 +8,7 @@ from airtimemetadata import AirtimeMetadata
 
 def encode_to(obj, encoding='utf-8'):
     if isinstance(obj, basestring):
-        if not isinstance(obj, string):
+        if not isinstance(obj, str):
             obj = obj.encode(encoding)
     return obj