diff --git a/azure_functions_worker/constants.py b/azure_functions_worker/constants.py
index 3edc039b0..a67eb144b 100644
--- a/azure_functions_worker/constants.py
+++ b/azure_functions_worker/constants.py
@@ -3,3 +3,6 @@
 TYPED_DATA_COLLECTION = "TypedDataCollection"
 RPC_HTTP_BODY_ONLY = "RpcHttpBodyOnly"
 RPC_HTTP_TRIGGER_METADATA_REMOVED = "RpcHttpTriggerMetadataRemoved"
+
+# Feature Flags (app settings)
+PYTHON_ROLLBACK_CWD_PATH = "PYTHON_ROLLBACK_CWD_PATH"
diff --git a/azure_functions_worker/dispatcher.py b/azure_functions_worker/dispatcher.py
index 62aedfc47..69f7d5d84 100644
--- a/azure_functions_worker/dispatcher.py
+++ b/azure_functions_worker/dispatcher.py
@@ -24,6 +24,7 @@
 
 from .logging import error_logger, logger
 from .tracing import marshall_exception_trace
+from .utils.wrappers import disable_feature_by
 
 
 class DispatcherMeta(type):
@@ -408,6 +409,12 @@ async def _handle__function_environment_reload_request(self, req):
                 logger.info('Unable to reload azure.functions. '
                             'Using default. Exception:\n{}'.format(ex))
 
+            # Change function app directory
+            if getattr(func_env_reload_request,
+                       'function_app_directory', None):
+                self._change_cwd(
+                    func_env_reload_request.function_app_directory)
+
             success_response = protos.FunctionEnvironmentReloadResponse(
                 result=protos.StatusResult(
                     status=protos.StatusResult.Success))
@@ -426,6 +433,14 @@ async def _handle__function_environment_reload_request(self, req):
                 request_id=self.request_id,
                 function_environment_reload_response=failure_response)
 
+    @disable_feature_by(constants.PYTHON_ROLLBACK_CWD_PATH)
+    def _change_cwd(self, new_cwd: str):
+        if os.path.exists(new_cwd):
+            os.chdir(new_cwd)
+            logger.info('Changing current working directory to %s', new_cwd)
+        else:
+            logger.warn('Directory %s is not found when reloading', new_cwd)
+
     def __run_sync_func(self, invocation_id, func, params):
         # This helper exists because we need to access the current
         # invocation_id from ThreadPoolExecutor's threads.
diff --git a/azure_functions_worker/testutils.py b/azure_functions_worker/testutils.py
index f8b5e905e..966539a4a 100644
--- a/azure_functions_worker/testutils.py
+++ b/azure_functions_worker/testutils.py
@@ -67,7 +67,11 @@
         "prefetchCount": 1000,
         "batchCheckpointFrequency": 1
     },
-    "functionTimeout": "00:05:00"
+    "functionTimeout": "00:05:00",
+    "extensionBundle": {
+        "id": "Microsoft.Azure.Functions.ExtensionBundle",
+        "version": "[1.*, 2.0.0)"
+    }
 }
 """
 
diff --git a/azure_functions_worker/utils/__init__.py b/azure_functions_worker/utils/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/azure_functions_worker/utils/common.py b/azure_functions_worker/utils/common.py
new file mode 100644
index 000000000..1c232f14e
--- /dev/null
+++ b/azure_functions_worker/utils/common.py
@@ -0,0 +1,15 @@
+import os
+
+
+def is_true_like(setting: str):
+    if setting is None:
+        return False
+
+    return setting.lower().strip() in ['1', 'true', 't', 'yes', 'y']
+
+
+def is_envvar_true(env_key: str):
+    if os.getenv(env_key) is None:
+        return False
+
+    return is_true_like(os.environ[env_key])
diff --git a/azure_functions_worker/utils/wrappers.py b/azure_functions_worker/utils/wrappers.py
new file mode 100644
index 000000000..15345c4d5
--- /dev/null
+++ b/azure_functions_worker/utils/wrappers.py
@@ -0,0 +1,21 @@
+from .common import is_envvar_true
+
+
+def enable_feature_by(flag: str, default=None):
+    def decorate(func):
+        def call(*args, **kwargs):
+            if is_envvar_true(flag):
+                return func(*args, **kwargs)
+            return default
+        return call
+    return decorate
+
+
+def disable_feature_by(flag: str, default=None):
+    def decorate(func):
+        def call(*args, **kwargs):
+            if not is_envvar_true(flag):
+                return func(*args, **kwargs)
+            return default
+        return call
+    return decorate
diff --git a/tests/unittests/load_functions/parentmodule/function.json b/tests/unittests/load_functions/parentmodule/function.json
new file mode 100644
index 000000000..12ff3cc01
--- /dev/null
+++ b/tests/unittests/load_functions/parentmodule/function.json
@@ -0,0 +1,15 @@
+{
+  "scriptFile": "sub_module/main.py",
+  "bindings": [
+    {
+      "type": "httpTrigger",
+      "direction": "in",
+      "name": "req"
+    },
+    {
+      "type": "http",
+      "direction": "out",
+      "name": "$return"
+    }
+  ]
+}
diff --git a/tests/unittests/load_functions/parentmodule/module.py b/tests/unittests/load_functions/parentmodule/module.py
new file mode 100644
index 000000000..2f4f1a61d
--- /dev/null
+++ b/tests/unittests/load_functions/parentmodule/module.py
@@ -0,0 +1 @@
+MODULE_NAME = 'PARENTMODULE'
diff --git a/tests/unittests/load_functions/parentmodule/sub_module/__init__.py b/tests/unittests/load_functions/parentmodule/sub_module/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/unittests/load_functions/parentmodule/sub_module/main.py b/tests/unittests/load_functions/parentmodule/sub_module/main.py
new file mode 100644
index 000000000..de09a6cec
--- /dev/null
+++ b/tests/unittests/load_functions/parentmodule/sub_module/main.py
@@ -0,0 +1,5 @@
+from .. import module
+
+
+def main(req) -> str:
+    return module.__name__
diff --git a/tests/unittests/load_functions/submodule/function.json b/tests/unittests/load_functions/submodule/function.json
new file mode 100644
index 000000000..5d4d8285f
--- /dev/null
+++ b/tests/unittests/load_functions/submodule/function.json
@@ -0,0 +1,15 @@
+{
+  "scriptFile": "main.py",
+  "bindings": [
+    {
+      "type": "httpTrigger",
+      "direction": "in",
+      "name": "req"
+    },
+    {
+      "type": "http",
+      "direction": "out",
+      "name": "$return"
+    }
+  ]
+}
diff --git a/tests/unittests/load_functions/submodule/main.py b/tests/unittests/load_functions/submodule/main.py
new file mode 100644
index 000000000..a8a4d1459
--- /dev/null
+++ b/tests/unittests/load_functions/submodule/main.py
@@ -0,0 +1,5 @@
+from .sub_module import module
+
+
+def main(req) -> str:
+    return module.__name__
diff --git a/tests/unittests/load_functions/submodule/sub_module/__init__.py b/tests/unittests/load_functions/submodule/sub_module/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/unittests/load_functions/submodule/sub_module/module.py b/tests/unittests/load_functions/submodule/sub_module/module.py
new file mode 100644
index 000000000..0dfdb5931
--- /dev/null
+++ b/tests/unittests/load_functions/submodule/sub_module/module.py
@@ -0,0 +1 @@
+MODULE_NAME = 'SUB_MODULE'
diff --git a/tests/unittests/test_loader.py b/tests/unittests/test_loader.py
index d65aff639..13ec18aa6 100644
--- a/tests/unittests/test_loader.py
+++ b/tests/unittests/test_loader.py
@@ -33,6 +33,16 @@ def test_loader_relimport(self):
         self.assertEqual(r.status_code, 200)
         self.assertEqual(r.text, '__app__.relimport.relative')
 
+    def test_loader_submodule(self):
+        r = self.webhost.request('GET', 'submodule')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.text, '__app__.submodule.sub_module.module')
+
+    def test_loader_parentmodule(self):
+        r = self.webhost.request('GET', 'parentmodule')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.text, '__app__.parentmodule.module')
+
 
 class TestPluginLoader(testutils.AsyncTestCase):
 
diff --git a/tests/unittests/test_rpc_messages.py b/tests/unittests/test_rpc_messages.py
index 796523078..40fcd104e 100644
--- a/tests/unittests/test_rpc_messages.py
+++ b/tests/unittests/test_rpc_messages.py
@@ -1,6 +1,8 @@
 import os
 import subprocess
 import sys
+import typing
+import tempfile
 
 from azure_functions_worker import protos
 from azure_functions_worker import testutils
@@ -8,14 +10,20 @@
 
 class TestGRPC(testutils.AsyncTestCase):
     pre_test_env = os.environ.copy()
+    pre_test_cwd = os.getcwd()
 
     def _reset_environ(self):
         for key, value in self.pre_test_env.items():
             os.environ[key] = value
+        os.chdir(self.pre_test_cwd)
 
-    async def _verify_environment_reloaded(self, test_env):
+    async def _verify_environment_reloaded(
+            self,
+            test_env: typing.Dict[str, str] = {},
+            test_cwd: str = os.getcwd()):
         request = protos.FunctionEnvironmentReloadRequest(
-            environment_variables=test_env)
+            environment_variables=test_env,
+            function_app_directory=test_cwd)
 
         request_msg = protos.StreamingMessage(
             request_id='0',
@@ -29,6 +37,7 @@ async def _verify_environment_reloaded(self, test_env):
 
             environ_dict = os.environ.copy()
             self.assertDictEqual(environ_dict, test_env)
+            self.assertEqual(os.getcwd(), test_cwd)
             status = r.function_environment_reload_response.result.status
             self.assertEqual(status, protos.StatusResult.Success)
         finally:
@@ -36,11 +45,20 @@ async def _verify_environment_reloaded(self, test_env):
 
     async def test_multiple_env_vars_load(self):
         test_env = {'TEST_KEY': 'foo', 'HELLO': 'world'}
-        await self._verify_environment_reloaded(test_env)
+        await self._verify_environment_reloaded(test_env=test_env)
 
     async def test_empty_env_vars_load(self):
         test_env = {}
-        await self._verify_environment_reloaded(test_env)
+        await self._verify_environment_reloaded(test_env=test_env)
+
+    async def test_changing_current_working_directory(self):
+        test_cwd = tempfile.gettempdir()
+        await self._verify_environment_reloaded(test_cwd=test_cwd)
+
+    async def test_reload_env_message(self):
+        test_env = {'TEST_KEY': 'foo', 'HELLO': 'world'}
+        test_cwd = tempfile.gettempdir()
+        await self._verify_environment_reloaded(test_env, test_cwd)
 
     def _verify_sys_path_import(self, result, expected_output):
         try:
diff --git a/tests/unittests/test_utilities.py b/tests/unittests/test_utilities.py
new file mode 100644
index 000000000..5b8f0c7b1
--- /dev/null
+++ b/tests/unittests/test_utilities.py
@@ -0,0 +1,122 @@
+import os
+import unittest
+import typing
+
+from azure_functions_worker.utils import common, wrappers
+
+
+TEST_FEATURE_FLAG = "APP_SETTING_FEATURE_FLAG"
+FEATURE_DEFAULT = 42
+
+
+class MockFeature:
+    @wrappers.enable_feature_by(TEST_FEATURE_FLAG)
+    def mock_feature_enabled(self, output: typing.List[str]) -> str:
+        result = 'mock_feature_enabled'
+        output.append(result)
+        return result
+
+    @wrappers.disable_feature_by(TEST_FEATURE_FLAG)
+    def mock_feature_disabled(self, output: typing.List[str]) -> str:
+        result = 'mock_feature_disabled'
+        output.append(result)
+        return result
+
+    @wrappers.enable_feature_by(TEST_FEATURE_FLAG, FEATURE_DEFAULT)
+    def mock_feature_default(self, output: typing.List[str]) -> str:
+        result = 'mock_feature_default'
+        output.append(result)
+        return result
+
+
+class TestUtilities(unittest.TestCase):
+
+    def setUp(self):
+        self._pre_env = dict(os.environ)
+
+    def tearDown(self):
+        os.environ.clear()
+        os.environ.update(self._pre_env)
+
+    def test_is_true_like_accepted(self):
+        self.assertTrue(common.is_true_like('1'))
+        self.assertTrue(common.is_true_like('true'))
+        self.assertTrue(common.is_true_like('T'))
+        self.assertTrue(common.is_true_like('YES'))
+        self.assertTrue(common.is_true_like('y'))
+
+    def test_is_true_like_rejected(self):
+        self.assertFalse(common.is_true_like(None))
+        self.assertFalse(common.is_true_like(''))
+        self.assertFalse(common.is_true_like('secret'))
+
+    def test_is_envvar_true(self):
+        os.environ[TEST_FEATURE_FLAG] = 'true'
+        self.assertTrue(common.is_envvar_true(TEST_FEATURE_FLAG))
+
+    def test_is_envvar_not_true_on_unset(self):
+        self._unset_feature_flag()
+        self.assertFalse(common.is_envvar_true(TEST_FEATURE_FLAG))
+
+    def test_disable_feature_with_no_feature_flag(self):
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_enabled(output)
+        self.assertIsNone(result)
+        self.assertListEqual(output, [])
+
+    def test_enable_feature_with_feature_flag(self):
+        feature_flag = TEST_FEATURE_FLAG
+        os.environ[feature_flag] = '1'
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_enabled(output)
+        self.assertEqual(result, 'mock_feature_enabled')
+        self.assertListEqual(output, ['mock_feature_enabled'])
+
+    def test_enable_feature_with_no_rollback_flag(self):
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_disabled(output)
+        self.assertEqual(result, 'mock_feature_disabled')
+        self.assertListEqual(output, ['mock_feature_disabled'])
+
+    def test_disable_feature_with_rollback_flag(self):
+        rollback_flag = TEST_FEATURE_FLAG
+        os.environ[rollback_flag] = '1'
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_disabled(output)
+        self.assertIsNone(result)
+        self.assertListEqual(output, [])
+
+    def test_enable_feature_with_rollback_flag_is_false(self):
+        rollback_flag = TEST_FEATURE_FLAG
+        os.environ[rollback_flag] = 'false'
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_disabled(output)
+        self.assertEqual(result, 'mock_feature_disabled')
+        self.assertListEqual(output, ['mock_feature_disabled'])
+
+    def test_fail_to_enable_feature_return_default_value(self):
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_default(output)
+        self.assertEqual(result, FEATURE_DEFAULT)
+        self.assertListEqual(output, [])
+
+    def test_disable_feature_with_false_flag_return_default_value(self):
+        feature_flag = TEST_FEATURE_FLAG
+        os.environ[feature_flag] = 'false'
+        mock_feature = MockFeature()
+        output = []
+        result = mock_feature.mock_feature_default(output)
+        self.assertEqual(result, FEATURE_DEFAULT)
+        self.assertListEqual(output, [])
+
+    def _unset_feature_flag(self):
+        try:
+            os.environ.pop(TEST_FEATURE_FLAG)
+        except KeyError:
+            pass