diff --git a/.travis.yml b/.travis.yml
index e079674..81f2908 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,6 +14,6 @@ python:
   - "nightly" # currently points to 3.7-dev
 install:
   - "pip install -r dev-requirements.txt"
-  - "pip install sendgrid"
+  - "pip install sendgrid==4.2.0"
   - "pip install django==$DJANGO_VERSION"
 script: nosetests -c nose.cfg
\ No newline at end of file
diff --git a/sendgrid_backend/version.py b/sendgrid_backend/version.py
index 611634e..832d8d8 100644
--- a/sendgrid_backend/version.py
+++ b/sendgrid_backend/version.py
@@ -1 +1 @@
-__version__ = "0.6.3a"
+__version__ = "0.6.4a"
diff --git a/setup.py b/setup.py
index 3cc9919..3474640 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@
 
 setup(
     name="django-sendgrid-v4",
-    version="0.6.3a",
+    version="0.6.4a0",
     description="An implementation of Django's EmailBackend compatible with sendgrid-python v4+",
     long_description=long_description,
     url="https://github.com/sklarsa/django-sendgrid-v4",
@@ -28,5 +28,5 @@
     ],
     keywords="django email sendgrid backend",
     packages=find_packages(exclude=["test", ]),
-    install_requires=["django >=1.8", "sendgrid >=4.0.0", "python-http-client >=2.3.0"]
+    install_requires=["django >=1.8", "sendgrid >=4.0.0, <4.2.1", "python-http-client >=2.3.0"]
 )