diff --git a/polars_iptools/iptools.py b/polars_iptools/iptools.py
index ea256fd..0227847 100644
--- a/polars_iptools/iptools.py
+++ b/polars_iptools/iptools.py
@@ -72,8 +72,15 @@ def numeric_to_ipv4(expr: IntoExpr) -> pl.Expr:
     """
     Returns IPv4 address string from its numeric representation
     """
+    # Convert to a polars expression if not already one
+    if isinstance(expr, str):
+        expr = pl.col(expr)
+    elif isinstance(expr, pl.Series):
+        expr = pl.lit(expr)
+
     # cast to UInt32 and leave any errors as nulls
-    expr = pl.select(expr).to_series().cast(pl.UInt32, strict=False)
+    expr = expr.cast(pl.UInt32, strict=False)
+
     return register_plugin_function(
         args=[expr],
         plugin_path=LIB,
diff --git a/polars_iptools/utils.py b/polars_iptools/utils.py
deleted file mode 100644
index c956fa4..0000000
--- a/polars_iptools/utils.py
+++ /dev/null
@@ -1,98 +0,0 @@
-from __future__ import annotations
-
-import re
-from pathlib import Path
-from typing import TYPE_CHECKING, Any, Sequence
-
-import polars as pl
-
-if TYPE_CHECKING:
-    from pathlib import Path
-
-    from polars.type_aliases import IntoExpr, PolarsDataType
-
-
-def get_shared_lib_location():
-    if parse_version(pl.__version__) < parse_version("0.20.16"):
-        from polars.utils.udfs import _get_shared_lib_location
-
-        return _get_shared_lib_location(__file__)
-    else:
-        return Path(__file__).parent
-
-
-def parse_into_expr(
-    expr: IntoExpr,
-    *,
-    str_as_lit: bool = False,
-    list_as_lit: bool = True,
-    dtype: PolarsDataType | None = None,
-) -> pl.Expr:
-    """
-    Parse a single input into an expression.
-
-    Parameters
-    ----------
-    expr
-        The input to be parsed as an expression.
-    str_as_lit
-        Interpret string input as a string literal. If set to `False` (default),
-        strings are parsed as column names.
-    list_as_lit
-        Interpret list input as a lit literal, If set to `False`,
-        lists are parsed as `Series` literals.
-    dtype
-        If the input is expected to resolve to a literal with a known dtype, pass
-        this to the `lit` constructor.
-
-    Returns
-    -------
-    polars.Expr
-    """
-    if isinstance(expr, pl.Expr):
-        pass
-    elif isinstance(expr, str) and not str_as_lit:
-        expr = pl.col(expr)
-    elif isinstance(expr, list) and not list_as_lit:
-        expr = pl.lit(pl.Series(expr), dtype=dtype)
-    else:
-        expr = pl.lit(expr, dtype=dtype)
-
-    return expr
-
-
-def register_plugin(
-    *,
-    symbol: str,
-    is_elementwise: bool,
-    kwargs: dict[str, Any] | None = None,
-    args: list[IntoExpr],
-    lib: str | Path,
-) -> pl.Expr:
-    if parse_version(pl.__version__) < parse_version("0.20.16"):
-        assert isinstance(args[0], pl.Expr)
-        assert isinstance(lib, str)
-        return args[0].register_plugin(
-            lib=lib,
-            symbol=symbol,
-            args=args[1:],
-            kwargs=kwargs,
-            is_elementwise=is_elementwise,
-        )
-    from polars.plugins import register_plugin_function
-
-    return register_plugin_function(
-        args=args,
-        plugin_path=lib,
-        function_name=symbol,
-        kwargs=kwargs,
-        is_elementwise=is_elementwise,
-    )
-
-
-def parse_version(version: Sequence[str | int]) -> tuple[int, ...]:
-    # Simple version parser; split into a tuple of ints for comparison.
-    # vendored from Polars
-    if isinstance(version, str):
-        version = version.split(".")
-    return tuple(int(re.sub(r"\D", "", str(v))) for v in version)
diff --git a/pyproject.toml b/pyproject.toml
index 3f2dbc3..24dfc4d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ["maturin>=1.0,<2.0", "polars>=0.20.6"]
+requires = ["maturin>=1.0,<2.0", "polars>=1.3.0"]
 build-backend = "maturin"
 
 [project]