diff --git a/requirements/py37.yml b/requirements/py37.yml
index 40e3a9d..321ba26 100644
--- a/requirements/py37.yml
+++ b/requirements/py37.yml
@@ -11,13 +11,13 @@ dependencies:
   - setuptools-scm
 
 # core dependencies
-  - cftime
+  - cftime >=1.5
   - matplotlib
   - numpy
 
 # test dependencies
   - codecov
-  - pytest>=6.0
+  - pytest >=6.0
   - pytest-cov
 
 # dev dependencies
diff --git a/requirements/py38.yml b/requirements/py38.yml
index 4f97610..1ff1b39 100644
--- a/requirements/py38.yml
+++ b/requirements/py38.yml
@@ -11,13 +11,13 @@ dependencies:
   - setuptools-scm
 
 # core dependencies
-  - cftime
+  - cftime >=1.5
   - matplotlib
   - numpy
 
 # test dependencies
   - codecov
-  - pytest>=6.0
+  - pytest >=6.0
   - pytest-cov
 
 # dev dependencies
diff --git a/requirements/py39.yml b/requirements/py39.yml
index e141ecb..d6519f1 100644
--- a/requirements/py39.yml
+++ b/requirements/py39.yml
@@ -11,13 +11,13 @@ dependencies:
   - setuptools-scm
 
 # core dependencies
-  - cftime
+  - cftime >=1.5
   - matplotlib
   - numpy
 
 # test dependencies
   - codecov
-  - pytest>=6.0
+  - pytest >=6.0
   - pytest-cov
 
 # dev dependencies
diff --git a/setup.cfg b/setup.cfg
index 8a0fe29..69c4fb7 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -34,7 +34,7 @@ version = attr: nc_time_axis.__version__
 [options]
 include_package_data = True
 install_requires =
-    cftime
+    cftime >=1.5
     matplotlib
     numpy
 packages = find: