diff --git a/versions.env b/versions.env
index 5f0429b..395d496 100644
--- a/versions.env
+++ b/versions.env
@@ -25,3 +25,9 @@ DOMAIN_WATCHDOG_VALKEY_IMAGE=valkey/valkey:9.1.2
 
 # --- oswl_connector (Flatcar) ---
 TAILSCALE_IMAGE=docker.io/tailscale/tailscale:v1.104.2
+
+# --- utility (Flatcar) ---
+# cturra/ntp only publishes "latest", so it is pinned by digest (2025-11-30 build).
+NTP_IMAGE=cturra/ntp@sha256:7224d4e7c7833aabbcb7dd70c46c8a8dcccda365314c6db047b9b10403ace3bc
+APT_CACHER_NG_IMAGE=mbentley/apt-cacher-ng:trixie-20261026
+REGISTRY_CACHE_IMAGE=registry:3.1.2