diff --git a/ChangeLog.md b/ChangeLog.md
index b9d1c87754d..68bf90c0a50 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,12 @@
 # Change Log
 
+### 2020-07-XX - 5.1.0-preview.4
+Modelerfour version: 4.15.378
+
+**New Features**
+
+- Enum values are uppercase (with an alias from the lowercase version)
+
 ### 2020-06-24 - 5.1.0-preview.3
 Modelerfour version: 4.13.351
 
diff --git a/README.md b/README.md
index 982ea2510c6..eb5e7dd1d03 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ pass-thru:
   - subset-reducer
 # version: 3.0.6258
 use-extension:
-  "@autorest/modelerfour": "4.13.351"
+  "@autorest/modelerfour": "4.15.378"
 
 modelerfour:
   group-parameters: true
diff --git a/package.json b/package.json
index e9e0dde2054..18e50df55dc 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@autorest/python",
-  "version": "5.1.0-preview.3",
+  "version": "5.1.0-preview.4",
   "description": "The Python extension for generators in AutoRest.",
   "scripts": {
     "prepare": "node run-python3.js prepare.py",
diff --git a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/__init__.py b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/__init__.py
index a892425d048..9eef844bef0 100644
--- a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/__init__.py
+++ b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/__init__.py
@@ -76,6 +76,7 @@
 from ._auto_rest_complex_test_service_enums import (
     CMYKColors,
     GoblinSharkColor,
+    MyKind,
 )
 
 __all__ = [
@@ -113,4 +114,5 @@
     'StringWrapper',
     'CMYKColors',
     'GoblinSharkColor',
+    'MyKind',
 ]
diff --git a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_auto_rest_complex_test_service_enums.py b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_auto_rest_complex_test_service_enums.py
index a496099ab4d..4195e9bcdb6 100644
--- a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_auto_rest_complex_test_service_enums.py
+++ b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_auto_rest_complex_test_service_enums.py
@@ -42,3 +42,7 @@ class GoblinSharkColor(with_metaclass(_CaseInsensitiveEnumMeta, str, Enum)):
     BROWN = "brown"
     UPPER_RED = "RED"  #: Uppercase RED.
     LOWER_RED = "red"  #: Lowercase RED.
+
+class MyKind(with_metaclass(_CaseInsensitiveEnumMeta, str, Enum)):
+
+    KIND1 = "Kind1"
diff --git a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models.py b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models.py
index bd0412f3446..fb442f4c09a 100644
--- a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models.py
+++ b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models.py
@@ -701,8 +701,8 @@ class MyBaseType(msrest.serialization.Model):
 
     All required parameters must be populated in order to send to Azure.
 
-    :param kind: Required. Constant filled by server.
-    :type kind: str
+    :param kind: Required. Constant filled by server.  Possible values include: "Kind1".
+    :type kind: str or ~bodycomplex.models.MyKind
     :param prop_b1:
     :type prop_b1: str
     :param prop_bh1:
@@ -738,8 +738,8 @@ class MyDerivedType(MyBaseType):
 
     All required parameters must be populated in order to send to Azure.
 
-    :param kind: Required. Constant filled by server.
-    :type kind: str
+    :param kind: Required. Constant filled by server.  Possible values include: "Kind1".
+    :type kind: str or ~bodycomplex.models.MyKind
     :param prop_b1:
     :type prop_b1: str
     :param prop_bh1:
diff --git a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models_py3.py b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models_py3.py
index 0ea1168c586..c51b318ac50 100644
--- a/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models_py3.py
+++ b/test/vanilla/Expected/AcceptanceTests/BodyComplex/bodycomplex/models/_models_py3.py
@@ -792,8 +792,8 @@ class MyBaseType(msrest.serialization.Model):
 
     All required parameters must be populated in order to send to Azure.
 
-    :param kind: Required. Constant filled by server.
-    :type kind: str
+    :param kind: Required. Constant filled by server.  Possible values include: "Kind1".
+    :type kind: str or ~bodycomplex.models.MyKind
     :param prop_b1:
     :type prop_b1: str
     :param prop_bh1:
@@ -832,8 +832,8 @@ class MyDerivedType(MyBaseType):
 
     All required parameters must be populated in order to send to Azure.
 
-    :param kind: Required. Constant filled by server.
-    :type kind: str
+    :param kind: Required. Constant filled by server.  Possible values include: "Kind1".
+    :type kind: str or ~bodycomplex.models.MyKind
     :param prop_b1:
     :type prop_b1: str
     :param prop_bh1: