diff --git a/definition-files/omb/Singularity.omb-5.6.3-ubuntu-18.04-openmpi-3.1.6 b/definition-files/omb/Singularity.omb-5.6.3-ubuntu-18.04-openmpi-3.1.6
index 16a0d3ff0d7b2bad93f588fe3ef2c50eff10fbed..d20e933fc66f2a329f07325961cfb7f6a7c0a888 100644
--- a/definition-files/omb/Singularity.omb-5.6.3-ubuntu-18.04-openmpi-3.1.6
+++ b/definition-files/omb/Singularity.omb-5.6.3-ubuntu-18.04-openmpi-3.1.6
@@ -1,5 +1,5 @@
-Bootstrap: shub
-From: mkandes/naked-singularity:ubuntu-18.04-openmpi-3.1.6
+Bootstrap: oras
+From: ghcr.io/mkandes/naked-singularity:ubuntu-18.04-openmpi-3.1.6
 
 %labels
 
@@ -10,7 +10,7 @@ From: mkandes/naked-singularity:ubuntu-18.04-openmpi-3.1.6
     AUTHOR_NAME Marty Kandes
     AUTHOR_EMAIL mkandes@sdsc.edu
 
-    LAST_UPDATED 20201228
+    LAST_UPDATED 20210803
 
 %setup
 
diff --git a/definition-files/ubuntu/Singularity.ubuntu-18.04-openmpi-3.1.6 b/definition-files/ubuntu/Singularity.ubuntu-18.04-openmpi-3.1.6
index 45a5562984c2c5d2d7868b45b636f8f644b1c53d..50be8d825dc316111b39178519f6a790a1450b07 100644
--- a/definition-files/ubuntu/Singularity.ubuntu-18.04-openmpi-3.1.6
+++ b/definition-files/ubuntu/Singularity.ubuntu-18.04-openmpi-3.1.6
@@ -1,5 +1,5 @@
-Bootstrap: shub
-From: mkandes/naked-singularity:ubuntu-18.04
+Bootstrap: oras
+From: ghcr.io/mkandes/naked-singularity:ubuntu-18.04
 
 %labels
 
@@ -10,7 +10,7 @@ From: mkandes/naked-singularity:ubuntu-18.04
     AUTHOR_NAME Marty Kandes
     AUTHOR_EMAIL mkandes@sdsc.edu
 
-    LAST_UPDATED 20210409
+    LAST_UPDATED 20210803
 
 %setup