diff --git a/business_rules/__init__.py b/business_rules/__init__.py
index dfea36f9..54e87a48 100644
--- a/business_rules/__init__.py
+++ b/business_rules/__init__.py
@@ -1,4 +1,4 @@
-__version__ = '1.4.1'
+__version__ = '1.4.2'
 
 from .engine import run_all, check_conditions_recursively
 from .utils import export_rule_data, validate_rule_data
diff --git a/business_rules/engine.py b/business_rules/engine.py
index 09cc3ca2..9b4c4810 100644
--- a/business_rules/engine.py
+++ b/business_rules/engine.py
@@ -6,6 +6,7 @@
 from .fields import FIELD_NO_INPUT
 from .models import ConditionResult
 from .util import method_type
+from .util.compat import getfullargspec
 
 logger = logging.getLogger(__name__)
 
@@ -230,7 +231,7 @@ def _build_variable_parameters(method, parameters, rule):
 
 
 def _build_parameters(method, parameters, extra_parameters):
-    if inspect.getargspec(method).keywords is not None:
+    if getfullargspec(method).varkw is not None:
         method_params = extra_parameters
     else:
         method_params = {}
diff --git a/business_rules/util/compat.py b/business_rules/util/compat.py
new file mode 100644
index 00000000..0caba58f
--- /dev/null
+++ b/business_rules/util/compat.py
@@ -0,0 +1,33 @@
+from __future__ import absolute_import, unicode_literals
+
+import sys
+from collections import namedtuple
+
+PY2 = sys.version_info[0] == 2
+
+# Taken from https://github.com/HypothesisWorks/hypothesis/pull/625/files#diff-e84a85b835af44101e1986c47ba39630R264
+if PY2:
+    FullArgSpec = namedtuple('FullArgSpec', 'args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations')
+
+    def getfullargspec(func):
+        import inspect
+        args, varargs, varkw, defaults = inspect.getargspec(func)
+        return FullArgSpec(args, varargs, varkw, defaults, [], None, {})
+else:
+    from inspect import getfullargspec
+
+    if sys.version_info[:2] == (3, 5):
+        # silence deprecation warnings on Python 3.5
+        # (un-deprecated in 3.6 to allow single-source 2/3 code like this)
+        def silence_warnings(func):
+            import warnings
+            import functools
+
+            @functools.wraps(func)
+            def inner(*args, **kwargs):
+                with warnings.catch_warnings():
+                    warnings.simplefilter('ignore', DeprecationWarning)
+                    return func(*args, **kwargs)
+            return inner
+
+        getfullargspec = silence_warnings(getfullargspec)
diff --git a/tests/test_engine_logic.py b/tests/test_engine_logic.py
index 2386eec3..2ee8d6f7 100644
--- a/tests/test_engine_logic.py
+++ b/tests/test_engine_logic.py
@@ -195,8 +195,8 @@ def test_check_operator_comparison(self):
     # ##################################### #
     def test_do_actions(self):
         function_params_mock = MagicMock()
-        function_params_mock.keywords = None
-        with patch('inspect.getargspec', return_value=function_params_mock):
+        function_params_mock.varkw = None
+        with patch('business_rules.engine.getfullargspec', return_value=function_params_mock):
             rule_actions = [
                 {
                     'name': 'action1'
@@ -232,8 +232,8 @@ def test_do_actions(self):
 
     def test_do_actions_with_injected_parameters(self):
         function_params_mock = MagicMock()
-        function_params_mock.keywords = True
-        with patch('inspect.getargspec', return_value=function_params_mock):
+        function_params_mock.varkw = True
+        with patch('business_rules.engine.getfullargspec', return_value=function_params_mock):
             rule_actions = [
                 {
                     'name': 'action1'