diff --git a/containers/eic/profile.d/z15_singularity_update.sh b/containers/eic/profile.d/z15_singularity_update.sh
new file mode 100644
index 000000000..9d96258c2
--- /dev/null
+++ b/containers/eic/profile.d/z15_singularity_update.sh
@@ -0,0 +1,43 @@
+#!/bin/bash
+
+## Warn users running singularity/apptainer when their outer eic-shell script is outdated.
+## Users can upgrade by running `eic-shell --upgrade` outside the container.
+
+# Only run for interactive shells
+case "$-" in
+  *i*) ;;
+  *) return 0 ;;
+esac
+
+# Only run when inside singularity/apptainer
+if [ -z "${SINGULARITY_CONTAINER:-}" ] && [ -z "${APPTAINER_CONTAINER:-}" ]; then
+  return 0
+fi
+
+# Require EIC_SHELL_PREFIX to be set; otherwise we cannot locate the outer eic-shell
+if [ -z "${EIC_SHELL_PREFIX:-}" ]; then
+  return 0
+fi
+
+# Check if the outer eic-shell script is accessible
+_outer_eic_shell="${EIC_SHELL_PREFIX}/../eic-shell"
+if [ ! -f "$_outer_eic_shell" ]; then
+  unset _outer_eic_shell
+  return 0
+fi
+
+# Only warn if we have write access (meaning user can upgrade)
+if [ ! -w "$_outer_eic_shell" ]; then
+  unset _outer_eic_shell
+  return 0
+fi
+
+# Warn if the outer eic-shell script is older than 6 months (~180 days)
+if [ -n "$(find "$_outer_eic_shell" -mtime +180 -print 2>/dev/null)" ]; then
+  echo ""
+  echo "WARNING: Your eic-shell script appears to be more than 6 months old."
+  echo "         Consider upgrading by running outside the container:"
+  echo "           eic-shell --upgrade"
+  echo ""
+fi
+unset _outer_eic_shell