diff --git a/defs-default b/defs-default
index 3b4d8c39aa4103a3edca8bd6992b5d395ef90d14..60d59680aec1c7382e07857c700ae1e5294ec6d2 100644
--- a/defs-default
+++ b/defs-default
@@ -35,7 +35,7 @@ WWWHOST=www.emulab.net
 TBMAINSITE=1
 THISHOMEBASE=Emulab.Net
 PLABSUPPORT=1
-PLAB_ROOTBALL="plabroot-15.tar.bz2"
+PLAB_ROOTBALL="plabroot-16.tar.bz2"
 MIN_UNIX_UID=10000
 MIN_UNIX_GID=6000
 WINSUPPORT=1