diff --git a/downloads-generation/models_class1_pan_refined/hyperparameters.yaml b/downloads-generation/models_class1_pan_refined/hyperparameters.yaml
index 8e40e769911d5389284df91084098f7b79866501..9dbb95757b5930a1fb7e346901efb1801cdaf83e 100644
--- a/downloads-generation/models_class1_pan_refined/hyperparameters.yaml
+++ b/downloads-generation/models_class1_pan_refined/hyperparameters.yaml
@@ -2,11 +2,12 @@
 # Batch generation
 #########################
 batch_generator_validation_split: 0.1
-batch_generator_batch_size: 1024
+batch_generator_batch_size: 10240
 batch_generator_affinity_fraction: 0.5
 max_epochs: 500
 random_negative_rate: 1.0
 random_negative_constant: 25
 learning_rate: 0.0001
 patience: 5
-min_delta: 0.0
\ No newline at end of file
+min_delta: 0.0
+loss_multiallelic_mass_spec_multiplier: 10
diff --git a/mhcflurry/downloads.yml b/mhcflurry/downloads.yml
index 3fdcf338eb9f730d442a23b10eddfe6b509c6582..5899f29a2d60db7783ce99e13fef89dcc8421a24 100644
--- a/mhcflurry/downloads.yml
+++ b/mhcflurry/downloads.yml
@@ -30,7 +30,7 @@ releases:
               default: false
 
             - name: models_class1_pan_refined
-              url: https://github.com/openvax/mhcflurry/releases/download/1.4.0/models_class1_pan_refined.20191209b.tar.bz2
+              url: https://github.com/openvax/mhcflurry/releases/download/1.4.0/models_class1_pan_refined.20191210.tar.bz2
               default: false
 
             - name: models_class1_pan_variants