diff --git a/requirements.txt b/requirements.txt
index 20c8b3e..49c737c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ matplotlib==2.1.0
 tensorflow
 numpy==1.13.3
 inflect==0.2.5
-librosa==0.6.0
+librosa==0.6.2
 scipy==1.0.0
 tensorboardX==1.1
 Unidecode==1.0.22
diff --git a/train.py b/train.py
index e8035c1..d83095d 100644
--- a/train.py
+++ b/train.py
@@ -41,8 +41,9 @@
 def load_checkpoint(checkpoint_path, model, optimizer):
     assert os.path.isfile(checkpoint_path)
     checkpoint_dict = torch.load(checkpoint_path, map_location='cpu')
-    iteration = checkpoint_dict['iteration']
-    optimizer.load_state_dict(checkpoint_dict['optimizer'])
+    iteration = checkpoint_dict.get('iteration', 0)
+    if 'optimizer' in checkpoint_dict:
+        optimizer.load_state_dict(checkpoint_dict['optimizer'])
     model_for_loading = checkpoint_dict['model']
     model.load_state_dict(model_for_loading.state_dict())
     print("Loaded checkpoint '{}' (iteration {})" .format(