diff --git a/var/spack/repos/builtin/packages/simplemoc/package.py b/var/spack/repos/builtin/packages/simplemoc/package.py
index 989bb5523d..b6e35abd95 100644
--- a/var/spack/repos/builtin/packages/simplemoc/package.py
+++ b/var/spack/repos/builtin/packages/simplemoc/package.py
@@ -33,9 +33,9 @@ class Simplemoc(MakefilePackage):
         light water reactor simulation."""
 
     homepage = "https://github.com/ANL-CESAR/SimpleMOC/"
-    url = "https://github.com/ANL-CESAR/SimpleMOC/archive/master.tar.gz"
+    url = "https://github.com/ANL-CESAR/SimpleMOC/archive/v4.tar.gz"
 
-    version('1.0', 'd8827221a4ae76e9766a32e16d143e60')
+    version('4', sha256='a39906014fdb234c43bf26e1919bdc8a13097788812e0b353a492b8e568816a6')
 
     tags = ['proxy-app']