diff --git a/README.md b/README.md
index aa53e7135..245b62ceb 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,10 @@
 ## News
 For details on the latest updates, see the [Changelog](https://github.com/Unidata/netcdf4-python/blob/master/Changelog).
 
+10/20/2023: Version [1.6.5](https://pypi.python.org/pypi/netCDF4/1.6.5) released. 
+Fix for issue #1271 (mask ignored if bool MA assinged to uint8 var), support for python 3.12, more
+informative error messages.
+
 6/4/2023:  Version [1.6.4](https://pypi.python.org/pypi/netCDF4/1.6.4) released.  Now requires 
 [certifi](https://github.com/certifi/python-certifi) to locate SSL certificates - this allows 
 OpenDAP https URLs to work with linux wheels (issue [#1246](https://github.com/Unidata/netcdf4-python/issues/1246)).
diff --git a/pyproject.toml b/pyproject.toml
index 01562cefb..70d00626c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,6 +39,14 @@ dependencies = [
 ]
 dynamic = ["version"]
 
+[project.optional-dependencies]
+tests = [
+  "Cython",
+  "packaging",
+  "pytest",
+]
+
+
 [project.readme]
 text = """\
 netCDF version 4 has many features not found in earlier versions of the library,
diff --git a/test/tst_multifile.py b/test/tst_multifile.py
index 0d9584892..93d72bded 100644
--- a/test/tst_multifile.py
+++ b/test/tst_multifile.py
@@ -5,7 +5,7 @@
 from numpy import ma
 import tempfile, unittest, os, datetime
 import cftime
-from pkg_resources import parse_version
+from packaging.version import Version
 
 nx=100; ydim=5; zdim=10
 nfiles = 10
@@ -138,7 +138,7 @@ def runTest(self):
         assert_equal(T.typecode(), t.typecode())
         # skip this until cftime pull request #55 is in a released
         # version (1.0.1?). Otherwise, fix for issue #808 breaks this
-        if parse_version(cftime.__version__) >= parse_version('1.0.1'):
+        if Version(cftime.__version__) >= Version('1.0.1'):
             assert_array_equal(cftime.num2date(T[:], T.units, T.calendar), dates)
         assert_equal(cftime.date2index(datetime.datetime(1980, 1, 2), T), 366)
         f.close()
diff --git a/test/tst_multifile2.py b/test/tst_multifile2.py
index f818fcaba..f8e8552a6 100644
--- a/test/tst_multifile2.py
+++ b/test/tst_multifile2.py
@@ -5,7 +5,7 @@
 from numpy import ma
 import tempfile, unittest, os, datetime
 import cftime
-from pkg_resources import parse_version
+from packaging.version import Version
 
 nx=100; ydim=5; zdim=10
 nfiles = 10
@@ -106,7 +106,7 @@ def runTest(self):
         # Get the real dates
         # skip this until cftime pull request #55 is in a released
         # version (1.0.1?). Otherwise, fix for issue #808 breaks this
-        if parse_version(cftime.__version__) >= parse_version('1.0.1'):
+        if Version(cftime.__version__) >= Version('1.0.1'):
             dates = []
             for file in self.files:
                 f = Dataset(file)
@@ -126,7 +126,7 @@ def runTest(self):
         assert_equal(T.typecode(), t.typecode())
         # skip this until cftime pull request #55 is in a released
         # version (1.0.1?). Otherwise, fix for issue #808 breaks this
-        if parse_version(cftime.__version__) >= parse_version('1.0.1'):
+        if Version(cftime.__version__) >= Version('1.0.1'):
             assert_array_equal(cftime.num2date(T[:], T.units, T.calendar), dates)
         assert_equal(cftime.date2index(datetime.datetime(1980, 1, 2), T), 366)
         f.close()