--- a/doc/conf.py
+++ b/doc/conf.py
@@ -134,8 +134,7 @@ source_encoding = "utf-8"
 master_doc = 'contents'
 
 # General substitutions.
-from subprocess import check_output
-SHA = check_output(['git', 'describe', '--dirty']).decode('utf-8').strip()
+SHA = None
 
 html_context = {'sha': SHA}