diff --git a/cabal.project b/cabal.project
index 9ef7a9600..a529fb194 100644
--- a/cabal.project
+++ b/cabal.project
@@ -1,6 +1,7 @@
 packages: gitit.cabal
 tests: True
 flags: +plugins
+constraints: bytestring >= 0.11.3
 
 package pandoc
   flags: +embed_data_files