diff --git a/testing/mozharness/README.txt b/testing/mozharness/README.txt
index a4b534a419d..df9233240e6 100644
--- a/testing/mozharness/README.txt
+++ b/testing/mozharness/README.txt
@@ -1,2 +1 @@
-mozharness.json is a manifest file that is currently only used on try.
-It allows you to lock mozharness to a repository and a revision.
+mozharness.json is a manifest file that locks or "pins" mozharness to a repository and a revision.
diff --git a/testing/mozharness/mozharness.json b/testing/mozharness/mozharness.json
index 9a89cf8eb92..dd5e8598de6 100644
--- a/testing/mozharness/mozharness.json
+++ b/testing/mozharness/mozharness.json
@@ -1,4 +1,4 @@
 {
     "repo": "https://hg.mozilla.org/build/mozharness",
-    "revision": "21f00dd7bda6"
+    "revision": "e170cecfdee2"
 }