diff --git a/update-all.sh b/update-all.sh
index 411cda0..c7e6494 100755
--- a/update-all.sh
+++ b/update-all.sh
@@ -58,8 +58,19 @@ step "sync-server-mods.sh"
 tooling/sync-server-mods.sh
 
 # ── 3. regenerate the landing mod list (mods.json + logos) ──────────
+# build-modlist.py needs stdlib tomllib (Python >=3.11). The host's default
+# `python3` may be older (e.g. Ubuntu 22.04 ships 3.10), so pick the first
+# interpreter that satisfies it rather than relying on the shebang.
 step "build-modlist.py"
-tooling/build-modlist.py
+PY=""
+for p in python3.13 python3.12 python3.11 python3; do
+  command -v "$p" >/dev/null 2>&1 || continue
+  if "$p" -c 'import sys; raise SystemExit(0 if sys.version_info >= (3, 11) else 1)' 2>/dev/null; then
+    PY="$p"; break
+  fi
+done
+[ -n "$PY" ] || { echo "no python >=3.11 found (build-modlist.py needs stdlib tomllib)" >&2; exit 1; }
+"$PY" tooling/build-modlist.py
 
 # ── 4. rebuild the landing site into www/ (gitignored — pull never
 #       updates it, so it must be rebuilt every run) ─────────────────