diff --git a/tiledb/ml/models/tensorflow_keras.py b/tiledb/ml/models/tensorflow_keras.py
index d5546310..31b50b04 100644
--- a/tiledb/ml/models/tensorflow_keras.py
+++ b/tiledb/ml/models/tensorflow_keras.py
@@ -279,6 +279,9 @@ def _serialize_optimizer_weights(
         assert self.artifact
         optimizer = self.artifact.optimizer
         if optimizer and not isinstance(optimizer, TFOptimizer):
-            optimizer_weights = tf.keras.backend.batch_get_value(optimizer.weights)
+            if hasattr(optimizer, "weights"):
+                optimizer_weights = tf.keras.backend.batch_get_value(optimizer.weights)
+            else:
+                optimizer_weights = [var.numpy() for var in optimizer.variables()]
             return pickle.dumps(optimizer_weights, protocol=4)
         return b""