--- a/testing/mozharness/scripts/release/postrelease_mark_as_shipped.py
+++ b/testing/mozharness/scripts/release/postrelease_mark_as_shipped.py
@@ -61,32 +61,32 @@ class MarkReleaseAsShipped(BaseScript, V
         super(MarkReleaseAsShipped, self)._pre_config_lock(rw_config)
         # override properties from buildbot properties here as defined by
         # taskcluster properties
         self.read_buildbot_config()
         if not self.buildbot_config:
             self.warning("Skipping buildbot properties overrides")
             return
         props = self.buildbot_config['properties']
-        mandatory_props = ['product', 'version', 'buildnumber']
+        mandatory_props = ['product', 'version', 'build_number']
         missing_props = []
         for prop in mandatory_props:
-            if props.get(prop):
+            if prop in props:
                 self.info("Overriding %s with %s" % (prop, props[prop]))
                 self.config[prop] = props.get(prop)
             else:
                 self.warning("%s could not be found within buildprops" % prop)
                 missing_props.append(prop)
 
         if missing_props:
             raise Exception("%s not found in configs" % missing_props)
 
         self.config['name'] = build_release_name(self.config['product'],
                                                  self.config['version'],
-                                                 self.config['buildnumber'])
+                                                 self.config['build_number'])
 
     def mark_as_shipped(self):
         """Method to make a simple call to Ship-it API to change a release
         status to 'shipped'
         """
         credentials_file = os.path.join(os.getcwd(),
                                         self.config["credentials_file"])
         credentials = {}