diff --git a/evaluate.py b/evaluate.py
index cf777f2..6d12600 100644
--- a/evaluate.py
+++ b/evaluate.py
@@ -122,22 +122,15 @@ def make_policy(envs):
     replay_helper.save(replay_file, compress=False)
     evaluator.close()
 
-def create_policy_ranker(policy_store_dir, ranker_file="openskill.pickle"):
+def create_policy_ranker(policy_store_dir, ranker_file="ranker.pickle", db_file="ranking.sqlite"):
     file = os.path.join(policy_store_dir, ranker_file)
     if os.path.exists(file):
-        if os.path.exists(file + ".lock"):
-            raise ValueError("Policy ranker file is locked. Delete the lock file.")
-        logging.info("Using policy ranker from %s", file)
-        policy_ranker = pufferlib.utils.PersistentObject(
-            file,
-            pufferlib.policy_ranker.OpenSkillRanker,
-        )
+        logging.info("Using existing policy ranker from %s", file)
+        policy_ranker = pufferlib.policy_ranker.OpenSkillRanker.load_from_file(file)
     else:
-        policy_ranker = pufferlib.utils.PersistentObject(
-            file,
-            pufferlib.policy_ranker.OpenSkillRanker,
-            "anchor",
-        )
+        logging.info("Creating a new policy ranker and db under %s", policy_store_dir)
+        db_file = os.path.join(policy_store_dir, db_file)
+        policy_ranker = pufferlib.policy_ranker.OpenSkillRanker(db_file, "anchor")
     return policy_ranker
 
 class AllPolicySelector(pufferlib.policy_ranker.PolicySelector):
@@ -198,8 +191,10 @@ def make_policy(envs):
         policy_selector=policy_selector,
     )
 
-    rank_file = os.path.join(policy_store_dir, "ranking.txt")
-    with open(rank_file, "w") as f:
+    ranker_file = os.path.join(policy_store_dir, "ranker.pickle")
+    # This is for quick viewing of the ranks, not for the actual ranking
+    rank_txt = os.path.join(policy_store_dir, "ranking.txt")
+    with open(rank_txt, "w") as f:
         pass
 
     results = defaultdict(list)
@@ -214,12 +209,13 @@ def make_policy(envs):
         ratings = evaluator.policy_ranker.ratings()
         dataframe = pd.DataFrame(
             {
-                ("Rating"): [ratings.get(n).mu for n in ratings],
+                ("Rating"): [ratings.get(n).get("mu") for n in ratings],
                 ("Policy"): ratings.keys(),
             }
         )
 
-        with open(rank_file, "a") as f:
+        ratings = evaluator.policy_ranker.save_to_file(ranker_file)
+        with open(rank_txt, "a") as f:
             f.write(
                 "\n\n"
                 + dataframe.round(2)
@@ -228,17 +224,6 @@ def make_policy(envs):
                 + "\n\n"
             )
 
-        # Reset the envs and start the new episodes
-        # NOTE: The below line will probably end the episode in the middle, 
-        #   so we won't be able to sample scores from the successful agents.
-        #   Thus, the scores will be biased towards the agents that die early.
-        #   Still, the numbers we get this way is better than frequently
-        #   updating the scores because the openskill ranking only takes the mean.
-        #evaluator.buffers[0]._async_reset()
-
-        # CHECK ME: delete the policy_ranker lock file
-        Path(evaluator.policy_ranker.lock.lock_file).unlink(missing_ok=True)
-
     evaluator.close()
     for pol, res in results.items():
         aggregated = {}
diff --git a/policies/puf04_70.000301.pt b/policies/puf41_seed425.000305.pt
similarity index 60%
rename from policies/puf04_70.000301.pt
rename to policies/puf41_seed425.000305.pt
index bfdc260..34a6347 100644
Binary files a/policies/puf04_70.000301.pt and b/policies/puf41_seed425.000305.pt differ
diff --git a/requirements.txt b/requirements.txt
index 8a14e35..116b096 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,6 +9,7 @@ ray==2.6.1
 scikit-learn==1.3.0
 tensorboard==2.11.2
 tiktoken==0.4.0
+torch==1.13.1
 torchtyping==0.1.4
 traitlets==5.9.0
 transformers==4.31.0