diff --git a/.github/workflows/lint_test.yml b/.github/workflows/lint_test.yml
index 02dedac..cd10eed 100644
--- a/.github/workflows/lint_test.yml
+++ b/.github/workflows/lint_test.yml
@@ -25,7 +25,7 @@ jobs:
     - name: Run black
       run: black . --check
     - name: Run ruff 
-      run: ruff . 
+      run: ruff check . 
     - name: Run mypy
       run: mypy . 
     - name: Run Tests
diff --git a/mappymatch/matchers/lcss/lcss.py b/mappymatch/matchers/lcss/lcss.py
index f6707ba..8f45f76 100644
--- a/mappymatch/matchers/lcss/lcss.py
+++ b/mappymatch/matchers/lcss/lcss.py
@@ -1,6 +1,5 @@
 import functools as ft
 import logging
-from multiprocessing import Pool
 
 from shapely.geometry import Point
 
@@ -152,10 +151,14 @@ def match_trace_batch(
         trace_batch: List[Trace],
         processes: int = 1,
     ) -> List[MatchResult]:
-        if processes > 1:
+        if processes <= 1:
             results = [self.match_trace(t) for t in trace_batch]
         else:
-            with Pool(processes=processes) as p:
-                results = p.map(self.match_trace, trace_batch)
+            raise NotImplementedError(
+                "Using `processes>1` is not available due to a known issue with rtree serialization."
+                "See https://github.com/Toblerity/rtree/issues/87 for more information."
+            )
+            # with Pool(processes=processes) as p:
+            #     results = p.map(self.match_trace, trace_batch)
 
         return results
diff --git a/mappymatch/matchers/match_result.py b/mappymatch/matchers/match_result.py
index 8629d8a..5eb89bd 100644
--- a/mappymatch/matchers/match_result.py
+++ b/mappymatch/matchers/match_result.py
@@ -21,7 +21,7 @@ def matches_to_dataframe(self) -> pd.DataFrame:
             A pandas dataframe
         """
         df = pd.DataFrame([m.to_flat_dict() for m in self.matches])
-        df = df.fillna(np.NAN)
+        df = df.fillna(np.nan)
 
         return df
 
@@ -37,6 +37,6 @@ def path_to_dataframe(self) -> pd.DataFrame:
             return pd.DataFrame()
 
         df = pd.DataFrame([r.to_flat_dict() for r in self.path])
-        df = df.fillna(np.NAN)
+        df = df.fillna(np.nan)
 
         return df
diff --git a/pyproject.toml b/pyproject.toml
index 88bab5d..906ca29 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "mappymatch"
-version = "0.4.4"
+version = "0.4.5"
 description = "Package for mapmatching."
 readme = "README.md"
 authors = [{ name = "National Renewable Energy Laboratory" }]