diff --git a/gli/io.py b/gli/io.py
index fc294831..39435a85 100644
--- a/gli/io.py
+++ b/gli/io.py
@@ -1,10 +1,12 @@
 """Helper functions for creating datasets in GLI format."""
+import datetime
 import json
 import os
 from typing import Dict, List, Optional, Tuple, Union
 import warnings
 import numpy as np
 from scipy.sparse import isspmatrix, spmatrix, coo_matrix
+import time
 
 from gli.utils import save_data
 
@@ -165,8 +167,7 @@ def save_graph(
                               description, cite, save_dir)
     # verify the inputs are dict for heterograph
     if not isinstance(edge, dict):
-        raise TypeError(
-            "The input edge must be a dictionary for heterograph.")
+        raise TypeError("The input edge must be a dictionary for heterograph.")
     if num_nodes is not None and not isinstance(num_nodes, dict):
         raise TypeError(
             "The input num_nodes must be a dictionary for heterograph.")
@@ -247,6 +248,11 @@ def _attr_to_metadata_dict(key_to_loc, prefix, a):
     return metadata
 
 
+def _get_version():
+    """Get the current utc time as the version."""
+    return datetime.datetime.now(datetime.timezone.utc).strftime("%Y%m%d%H%M%S")
+
+
 def save_homograph(
     name: str,
     edge: np.ndarray,
@@ -455,6 +461,10 @@ def save_homograph(
 
     metadata["citation"] = citation
     metadata["is_heterogeneous"] = False
+    metadata["version"] = _get_version()
+    print("The graph metadata is saved to",
+          os.path.join(save_dir, "metadata.json"))
+    print("Version:", metadata["version"])
 
     if citation == "":
         warnings.warn("The citation is empty.")
@@ -907,6 +917,10 @@ def save_heterograph(
         graph_dict[attr.name] = _attr_to_metadata_dict(key_to_loc, "Graph",
                                                        attr)
     metadata["data"]["Graph"] = graph_dict
+    metadata["version"] = _get_version()
+    print("The graph metadata is saved to",
+          os.path.join(save_dir, "metadata.json"))
+    print("Version:", metadata["version"])
 
     if citation == "":
         warnings.warn("The citation is empty.")
@@ -969,6 +983,14 @@ def _check_feature(feature):
             "Each element in `feature` must be a node/edge/graph attribute."
 
 
+def _get_metadata_version(metadata):
+    """Check the version of the metadata is valid."""
+    assert "version" in metadata, \
+        "The metadata does not contain the version information." \
+        "Please add the version information to the metadata."
+    return metadata["version"]
+
+
 def _save_task_reg_or_cls(task_type,
                           name,
                           description,
@@ -1078,6 +1100,12 @@ def _save_task_reg_or_cls(task_type,
                                                       val_ratio, test_ratio,
                                                       num_samples)
 
+    # Check if metadata.json exists.
+    metadata_path = os.path.join(save_dir, "metadata.json")
+    assert os.path.exists(metadata_path), \
+        "metadata.json does not exist. Please create it first."
+    current_metadata_version = _get_metadata_version(metadata_path)
+
     # Task-dependent checks.
     if task_type in ("NodeClassification", "NodeRegression"):
         assert target.startswith("Node/"), \
@@ -1096,7 +1124,8 @@ def _save_task_reg_or_cls(task_type,
         "description": description,
         "type": task_type,
         "feature": feature,
-        "target": target
+        "target": target,
+        "version": current_metadata_version,
     }
     if num_classes is not None:
         task_dict["num_classes"] = num_classes
@@ -1141,7 +1170,8 @@ def save_task_node_regression(name,
                               test_ratio=0.1,
                               num_samples=None,
                               task_id=1,
-                              save_dir="."):
+                              save_dir=".",
+                              latest_supported_ver=None):
     """Save the node regression task information into task json and data files.
 
     :param name: The name of the dataset.
@@ -1200,6 +1230,8 @@ def save_task_node_regression(name,
     :param save_dir: The directory to save the task json and data files.
         Default: ".".
     :type save_dir: str
+    :param latest_supported_ver: The latest supported version of the metadata.
+    :type latest_supported_ver: str
 
     :raises ValueError: If `task_type` is not "NodeRegression" or
         "NodeClassification".
@@ -1285,7 +1317,8 @@ def save_task_node_regression(name,
                                  test_ratio=test_ratio,
                                  num_samples=num_samples,
                                  task_id=task_id,
-                                 save_dir=save_dir)
+                                 save_dir=save_dir,
+                                 latest_supported_ver=latest_supported_ver)
 
 
 def save_task_node_classification(name,
@@ -1301,7 +1334,8 @@ def save_task_node_classification(name,
                                   test_ratio=0.1,
                                   num_samples=None,
                                   task_id=1,
-                                  save_dir="."):
+                                  save_dir=".",
+                                  latest_supported_ver=None):
     """Save the node classification task information into task json and data files.
 
     :param name: The name of the dataset.
@@ -1450,4 +1484,5 @@ def save_task_node_classification(name,
                                  test_ratio=test_ratio,
                                  num_samples=num_samples,
                                  task_id=task_id,
-                                 save_dir=save_dir)
+                                 save_dir=save_dir,
+                                 latest_supported_ver=latest_supported_ver)