diff --git a/pyproject.toml b/pyproject.toml
index 9b9440e7..63376d8b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,7 +19,7 @@ classifiers = [
     "Operating System :: OS Independent",
 ]
 dependencies = [
-    "numpy>=1.20, <2.0",
+    "numpy>=1.20",
     "scipy",
     "xarray",
     "autograd",
diff --git a/tests/test_integration.py b/tests/test_integration.py
index 739956d0..60618864 100644
--- a/tests/test_integration.py
+++ b/tests/test_integration.py
@@ -301,7 +301,7 @@ def test_p_controller_resonant_wave(self,
                         scale_x_opt=1e-3,
                         scale_obj=1e-1,
                         optim_options={'ftol': 1e-10},
-                        bounds_opt=((-1*np.infty, 0),),
+                        bounds_opt=((-1*np.inf, 0),),
                         )
 
         power_sol = -1*res[0]['fun']
diff --git a/wecopttool/core.py b/wecopttool/core.py
index 40ca2a1b..8c10a2d3 100644
--- a/wecopttool/core.py
+++ b/wecopttool/core.py
@@ -58,7 +58,7 @@
 from typing import Iterable, Callable, Any, Optional, Mapping, TypeVar, Union
 from pathlib import Path
 import warnings
-from datetime import datetime
+import datetime
 
 from numpy.typing import ArrayLike
 import autograd.numpy as np
@@ -80,7 +80,7 @@
 warnings.filterwarnings("ignore", message=filter_msg)
 
 # default values
-_default_parameters = {'rho': 1025.0, 'g': 9.81, 'depth': np.infty}
+_default_parameters = {'rho': 1025.0, 'g': 9.81, 'depth': np.inf}
 _default_min_damping = 1e-6
 
 # type aliases
@@ -895,7 +895,7 @@ def post_process(self,
                                 "post-process and be passed as an input.")
 
         def _postproc(res, waves, nsubsteps):
-            create_time = f"{datetime.utcnow()}"
+            create_time = f"{datetime.datetime.now(datetime.UTC)}"
 
             omega_vals = np.concatenate([[0], waves.omega.values])
             freq_vals = np.concatenate([[0], waves.freq.values])
@@ -1060,7 +1060,7 @@ def omega(self) -> ndarray:
     @property
     def period(self) -> ndarray:
         """Period vector [s]."""
-        return np.concatenate([[np.Infinity], 1/self._freq[1:]])
+        return np.concatenate([[np.inf], 1/self._freq[1:]])
 
     @property
     def w1(self) -> float:
@@ -2109,7 +2109,7 @@ def standard_forces(hydro_data: Dataset) -> TForceDict:
 
 def run_bem(
     fb: cpy.FloatingBody,
-    freq: Iterable[float] = [np.infty],
+    freq: Iterable[float] = [np.inf],
     wave_dirs: Iterable[float] = [0],
     rho: float = _default_parameters['rho'],
     g: float = _default_parameters['g'],
diff --git a/wecopttool/pto.py b/wecopttool/pto.py
index 7ff85db5..050f42ff 100644
--- a/wecopttool/pto.py
+++ b/wecopttool/pto.py
@@ -34,7 +34,7 @@
 from scipy.linalg import block_diag
 from scipy.optimize import OptimizeResult
 from xarray import DataArray, Dataset
-from datetime import datetime
+import datetime
 from scipy.optimize import OptimizeResult
 
 from wecopttool.core import complex_to_real, td_to_fd
@@ -707,7 +707,7 @@ def post_process(self,
         """
         def _postproc(wec, res, waves, nsubsteps):
 
-            create_time = f"{datetime.utcnow()}"
+            create_time = f"{datetime.datetime.now(datetime.UTC)}"
 
             x_wec, x_opt = wec.decompose_state(res.x)