diff --git a/.github/workflows/python-tests.yml b/.github/workflows/python-tests.yml
index 0fc5408..d7512d3 100644
--- a/.github/workflows/python-tests.yml
+++ b/.github/workflows/python-tests.yml
@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12"]
 
     steps:
       - name: Check out repository
diff --git a/README.md b/README.md
index baeb59e..daacb20 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ lengths, or whether an identifier is real.
 
 ## Requirements
 
-- Python 3.8+
+- Python 3.10+
 - No third-party packages
 
 ## Quick Start
@@ -95,8 +95,9 @@ space  -  .  /  \  ,
 
 After normalization, the value must contain at least one digit and no other
 characters. `checksum`, `calculate_check_digit`, and `append_check_digit` raise
-`ValueError` for invalid input. `is_valid` catches that error and returns
-`False`, which makes it convenient for validation checks.
+`ValueError` for malformed strings and `TypeError` for unsupported input types.
+`is_valid` catches both errors and returns `False`, which makes it convenient
+for validation checks.
 
 ## Examples
 
diff --git a/luhn.py b/luhn.py
index c40ae14..a68b4a0 100644
--- a/luhn.py
+++ b/luhn.py
@@ -2,9 +2,7 @@
 
 from __future__ import annotations
 
-from typing import Union
-
-NumberLike = Union[str, int]
+NumberLike = str | int
 REMOVE_CHARS = " -./\\,"
 DIGIT_CLEANUP_TABLE = str.maketrans("", "", REMOVE_CHARS)
 
@@ -12,7 +10,7 @@
 def _digits(value: NumberLike) -> str:
     """Return only digits, allowing spaces, hyphens, dots, slashes, backslashes, and commas as separators."""
     if isinstance(value, bool) or not isinstance(value, (str, int)):
-        raise ValueError("value must be a string or non-boolean integer")
+        raise TypeError("value must be a string or non-boolean integer")
 
     cleaned = str(value).strip().translate(DIGIT_CLEANUP_TABLE)
 
@@ -51,7 +49,7 @@ def is_valid(value: NumberLike) -> bool:
 
     try:
         is_valid_checksum = checksum(value) == 0
-    except ValueError:
+    except (TypeError, ValueError):
         return False
 
     return is_valid_checksum
diff --git a/pyproject.toml b/pyproject.toml
index ce924c7..bff3f5b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,5 @@
 [project]
 name = "luhn-algorithm"
 version = "0.1.0"
-requires-python = ">=3.14"
+requires-python = ">=3.10"
 dependencies = []
diff --git a/test_luhn.py b/test_luhn.py
index b5d0d18..5b0c8ba 100644
--- a/test_luhn.py
+++ b/test_luhn.py
@@ -38,7 +38,7 @@ def test_rejects_unsupported_types(self):
                 self.assertFalse(is_valid(value))
 
                 for function in (checksum, calculate_check_digit, append_check_digit):
-                    with self.assertRaises(ValueError):
+                    with self.assertRaises(TypeError):
                         function(value)
 
 
diff --git a/uv.lock b/uv.lock
index 0b51f55..56d27ab 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1,6 +1,6 @@
 version = 1
 revision = 3
-requires-python = ">=3.14"
+requires-python = ">=3.10"
 
 [[package]]
 name = "luhn-algorithm"