diff --git a/custodian/__init__.py b/custodian/__init__.py
index e63c7146..3faaeb67 100644
--- a/custodian/__init__.py
+++ b/custodian/__init__.py
@@ -4,6 +4,7 @@
 """
 
 import os
+from importlib.metadata import PackageNotFoundError, version
 
 from .custodian import Custodian
 
@@ -11,7 +12,11 @@
     "Shyue Ping Ong, William Davidson Richards, Stephen Dacek, Xiaohui Qu, Matthew Horton, "
     "Samuel M. Blau, Janosh Riebesell"
 )
-__version__ = "2024.4.18"
+try:
+    __version__ = version("pymatgen")
+except PackageNotFoundError:  # pragma: no cover
+    # package is not installed
+    pass
 
 
 PKG_DIR = os.path.dirname(__file__)
diff --git a/tasks.py b/tasks.py
index f2cf6aba..6d8ea479 100644
--- a/tasks.py
+++ b/tasks.py
@@ -71,12 +71,6 @@ def test(ctx) -> None:
 
 @task
 def set_ver(ctx) -> None:
-    with open("custodian/__init__.py") as file:
-        lines = [f'__version__ = "{NEW_VER}"' if "__version__" in line else line.rstrip() for line in file]
-
-    with open("custodian/__init__.py", "w") as file:
-        file.write("\n".join(lines) + "\n")
-
     with open("pyproject.toml") as file:
         lines = [re.sub(r"^version = \"([^,]+)\"", f'version = "{NEW_VER}"', line.rstrip()) for line in file]