diff --git a/migrations/201606210001_devices_udid_idx_down.sql b/migrations/201606210001_devices_udid_idx_down.sql
deleted file mode 100644
index 8fb7c277..00000000
--- a/migrations/201606210001_devices_udid_idx_down.sql
+++ /dev/null
@@ -1 +0,0 @@
-DROP INDEX udid_idx;
diff --git a/migrations/201606210001_devices_udid_idx_up.sql b/migrations/201606210001_devices_udid_idx_up.sql
deleted file mode 100644
index db237b64..00000000
--- a/migrations/201606210001_devices_udid_idx_up.sql
+++ /dev/null
@@ -1 +0,0 @@
-CREATE UNIQUE INDEX IF NOT EXISTS udid_idx ON devices (udid);
diff --git a/migrations/201606210002_devices_udid_idx_down.sql b/migrations/201606210002_devices_udid_idx_down.sql
new file mode 100644
index 00000000..7816857a
--- /dev/null
+++ b/migrations/201606210002_devices_udid_idx_down.sql
@@ -0,0 +1 @@
+DROP INDEX udid_serial_idx;
diff --git a/migrations/201606210002_devices_udid_idx_up.sql b/migrations/201606210002_devices_udid_idx_up.sql
new file mode 100644
index 00000000..a2ce7844
--- /dev/null
+++ b/migrations/201606210002_devices_udid_idx_up.sql
@@ -0,0 +1,4 @@
+DROP INDEX serial_idx;
+
+-- Need a composite constraint because DEP uses serial and OTA enrollment uses UDID
+CREATE UNIQUE INDEX IF NOT EXISTS udid_serial_idx ON devices (udid, serial_number);