diff --git a/buildout.cfg b/buildout.cfg
index a2ac5a2..1edb962 100644
--- a/buildout.cfg
+++ b/buildout.cfg
@@ -51,6 +51,8 @@ eggs = ${test:eggs}
 [versions]
 # use latest version of coverage
 coverage =
+# XXX: https://github.com/timothycrosley/isort/issues/409
+isort = 4.2.2
 
 [node]
 version = 4.0.0