diff --git a/satpy/readers/aapp_mhs_amsub_l1c.py b/satpy/readers/aapp_mhs_amsub_l1c.py
index 39216431f4..f5765545f3 100644
--- a/satpy/readers/aapp_mhs_amsub_l1c.py
+++ b/satpy/readers/aapp_mhs_amsub_l1c.py
@@ -152,7 +152,7 @@ def _calibrate(data,
     if calib_type == 'counts':
         return channel
 
-    channel = channel.astype(np.float_)
+    channel = channel.astype(np.float64)
 
     return da.where(mask, channel, np.nan)
 
diff --git a/satpy/readers/hdf4_utils.py b/satpy/readers/hdf4_utils.py
index acc86fd64d..fb20c0ce11 100644
--- a/satpy/readers/hdf4_utils.py
+++ b/satpy/readers/hdf4_utils.py
@@ -69,7 +69,7 @@ def __init__(self, filename, filename_info, filetype_info):
     def _collect_attrs(self, name, attrs):
         for key, value in attrs.items():
             value = np.squeeze(value)
-            if issubclass(value.dtype.type, (np.string_, np.unicode_)) and not value.shape:
+            if issubclass(value.dtype.type, (np.bytes_, np.str_)) and not value.shape:
                 value = value.item()  # convert to scalar
                 if not isinstance(value, str):
                     # python 3 - was scalar numpy array of bytes
diff --git a/satpy/readers/utils.py b/satpy/readers/utils.py
index 31f6dea6d9..e2035af479 100644
--- a/satpy/readers/utils.py
+++ b/satpy/readers/utils.py
@@ -54,7 +54,7 @@ def np2str(value):
 
     """
     if hasattr(value, 'dtype') and \
-            issubclass(value.dtype.type, (np.str_, np.string_, np.object_)) \
+            issubclass(value.dtype.type, (np.str_, np.bytes_, np.object_)) \
             and value.size == 1:
         value = value.item()
         if not isinstance(value, str):
diff --git a/satpy/tests/reader_tests/test_utils.py b/satpy/tests/reader_tests/test_utils.py
index 54b156e4c5..fc38e36c88 100644
--- a/satpy/tests/reader_tests/test_utils.py
+++ b/satpy/tests/reader_tests/test_utils.py
@@ -202,20 +202,20 @@ def test_sub_area(self, adef):
     def test_np2str(self):
         """Test the np2str function."""
         # byte object
-        npstring = np.string_('hej')
-        self.assertEqual(hf.np2str(npstring), 'hej')
+        npbytes = np.bytes_('hej')
+        self.assertEqual(hf.np2str(npbytes), 'hej')
 
         # single element numpy array
-        np_arr = np.array([npstring])
+        np_arr = np.array([npbytes])
         self.assertEqual(hf.np2str(np_arr), 'hej')
 
         # scalar numpy array
-        np_arr = np.array(npstring)
+        np_arr = np.array(npbytes)
         self.assertEqual(hf.np2str(np_arr), 'hej')
 
         # multi-element array
-        npstring = np.array([npstring, npstring])
-        self.assertRaises(ValueError, hf.np2str, npstring)
+        npbytes = np.array([npbytes, npbytes])
+        self.assertRaises(ValueError, hf.np2str, npbytes)
 
         # non-array
         self.assertRaises(ValueError, hf.np2str, 5)
diff --git a/satpy/tests/writer_tests/test_cf.py b/satpy/tests/writer_tests/test_cf.py
index a325cb9cc8..a034038663 100644
--- a/satpy/tests/writer_tests/test_cf.py
+++ b/satpy/tests/writer_tests/test_cf.py
@@ -537,7 +537,7 @@ def get_test_attrs(self):
                  'numpy_bool': True,
                  'numpy_void': np.void(0),
                  'numpy_bytes': np.bytes_('test'),
-                 'numpy_string': np.string_('test'),
+                 'numpy_string': np.str_('test'),
                  'list': [1, 2, np.float64(3)],
                  'nested_list': ["1", ["2", [3]]],
                  'bool': True,
diff --git a/satpy/writers/cf_writer.py b/satpy/writers/cf_writer.py
index b9a24b9292..702e25c2fa 100644
--- a/satpy/writers/cf_writer.py
+++ b/satpy/writers/cf_writer.py
@@ -192,7 +192,7 @@
 if netCDF4 is None and h5netcdf is None:
     raise ImportError('Ensure that the netCDF4 or h5netcdf package is installed.')
 
-# Numpy datatypes compatible with all netCDF4 backends. ``np.unicode_`` is
+# Numpy datatypes compatible with all netCDF4 backends. ``np.str_`` is
 # excluded because h5py (and thus h5netcdf) has problems with unicode, see
 # https://github.com/h5py/h5py/issues/624."""
 NC4_DTYPES = [np.dtype('int8'), np.dtype('uint8'),
@@ -200,7 +200,7 @@
               np.dtype('int32'), np.dtype('uint32'),
               np.dtype('int64'), np.dtype('uint64'),
               np.dtype('float32'), np.dtype('float64'),
-              np.string_]
+              np.bytes_]
 
 # Unsigned and int64 isn't CF 1.7 compatible
 # Note: Unsigned and int64 are CF 1.9 compatible
@@ -209,7 +209,7 @@
              np.dtype('int32'),
              np.dtype('float32'),
              np.dtype('float64'),
-             np.string_]
+             np.bytes_]
 
 CF_VERSION = 'CF-1.7'
 
@@ -582,7 +582,7 @@ def _remove_satpy_attrs(new_data):
 def _format_prerequisites_attrs(dataarray):
     """Reformat prerequisites attribute value to string."""
     if 'prerequisites' in dataarray.attrs:
-        dataarray.attrs['prerequisites'] = [np.string_(str(prereq)) for prereq in dataarray.attrs['prerequisites']]
+        dataarray.attrs['prerequisites'] = [np.bytes_(str(prereq)) for prereq in dataarray.attrs['prerequisites']]
     return dataarray
 
 
diff --git a/setup.py b/setup.py
index 612db4fa05..555f299b19 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@
 
 from setuptools import find_packages, setup
 
-requires = ['numpy >=1.13', 'pillow', 'pyresample >=1.24.0', 'trollsift',
+requires = ['numpy >=1.21', 'pillow', 'pyresample >=1.24.0', 'trollsift',
             'trollimage >=1.20', 'pykdtree', 'pyyaml >=5.1', 'xarray >=0.10.1, !=0.13.0',
             'dask[array] >=0.17.1', 'pyproj>=2.2', 'zarr', 'donfig', 'appdirs',
             'packaging', 'pooch', 'pyorbital']