diff --git a/utils/update_build_version.py b/utils/update_build_version.py
index 0f68bf5e4..98ab5b16d 100755
--- a/utils/update_build_version.py
+++ b/utils/update_build_version.py
@@ -54,14 +54,14 @@ def command_output(cmd, dir):
     return stdout
 
 
-def deduceSoftwareVersion(dir):
+def deduce_software_version(dir):
     """Returns a software version number parsed from the CHANGES file
     in the given dir.
 
     The CHANGES file describes most recent versions first.
     """
 
-    pattern = re.compile('(v\d+\.\d+(-dev)) \d\d\d\d-\d\d-\d\d$')
+    pattern = re.compile('(v\d+\.\d+(-dev)?) \d\d\d\d-\d\d-\d\d$')
     changes_file = os.path.join(dir, 'CHANGES')
     with open(changes_file) as f:
         for line in f.readlines():
@@ -99,7 +99,7 @@ def main():
 
     output_file = sys.argv[2]
 
-    software_version = deduceSoftwareVersion(sys.argv[1])
+    software_version = deduce_software_version(sys.argv[1])
     new_content = '"{}", "SPIRV-Tools {} {}"\n'.format(
         software_version, software_version,
         describe(sys.argv[1]).replace('"', '\\"'))