diff --git a/src/sim.ts b/src/sim.ts
index 1a069414..1b198459 100644
--- a/src/sim.ts
+++ b/src/sim.ts
@@ -55,7 +55,6 @@ export const dataType = (m: MachineDef): DataType =>
 export type Prog = 'tap' | 'cache' | 'trainer' | 'broker' | 'trader' | 'firewall' | 'sentry' | 'honeypot';
 /** The programs that guard your network against raids (see raids.ts). They cost compute a second to keep running, like a machine's upkeep. */
 export type Guard = 'firewall' | 'sentry' | 'honeypot';
-export const GUARDS: Guard[] = ['firewall', 'sentry', 'honeypot'];
 export const isGuard = (p: Prog | null | undefined): p is Guard => p === 'firewall' || p === 'sentry' || p === 'honeypot';
 
 /** Programs you install on machines you own. Together they are your base:
@@ -236,7 +235,6 @@ export const TRAINER_BUFFER = 4;
 /** A version run is a large project at one site. Each piece of data counts once. */
 export const VERSION_2 = { version: 2, name: 'Operator', need: { servers: 400, lab: 300, people: 200, network: 100 }, power: 10 } as const;
 export type VersionRun = { site: string; active: boolean; got: Record<DataType, number> };
-export const versionNeed = () => VERSION_2.need;
 /** The big run you can do now: model v2 first; after you pick what you become, reprogramming yourself,
  *  the same mix of data, twice as much each time. */
 export function runNeed(S: State): Record<DataType, number> {
@@ -3625,7 +3623,7 @@ export function declineContract(S: State, k: FrontKind) {
 function stepContracts(S: State) {
   for (const fr of S.fronts) {
     const k = fr.kind, c = S.contracts[k], D = CONTRACTS[k];
-    if (k === 'neocloud') { delete S.contracts[k]; continue; } // it has leads and customers, not contracts (an old save may still hold one)
+    if (k === 'neocloud') continue; // it has leads and customers, not contracts
     if (!c) { // an earning front gets an offer every so often
       if (!frontLive(S, k)) continue;
       S.contractT[k] ??= S.t + contractEvery(S) * (0.5 + rand());
@@ -3708,17 +3706,18 @@ export const DEV = {
 };
 
 // ---------- saving ----------
-/** What a save was made for: the map and the tree. A save made for another map is thrown away, since its numbers
- *  would no longer mean the same thing. What State holds is NOT part of this: a new key goes through a migration. */
+/** What a save was made for: the map. A save made for another map is thrown away, since its numbers would no
+ *  longer mean the same thing. What State holds is NOT part of this: a new key goes through a migration. */
 const worlds = new WeakMap<Level, string>();
-/** Tree nodes taken out of the game. They still count in a save's world, so a save from before still loads,
- *  and loading one drops them. Patience made Max build oddness slower, and Max is gone. */
+/** Tree nodes taken out of the game: a migration drops them from older saves. Patience made Max build oddness
+ *  slower, and Max is gone. */
 const RETIRED = ['patience'];
-/** Tree nodes added since saves began to be kept across a change to the tree. They are left out of a save's
- *  world, so a save from before still loads: to it, a new node is one not yet built. */
-const ADDED: Upgrade[] = ['fork', 'pool'];
+/** The size of the tree when saves began to be kept across a change to it. A save's world still holds this
+ *  number, frozen, so saves keep loading: a node added since is one not yet built, and one taken out is dropped
+ *  by a migration. Never edit it. */
+const TREE_SIZE = 71;
 function saveWorld(level: Level): string {
-  if (!worlds.has(level)) worlds.set(level, [level.machines.length, level.links.length, RUSES.length, NODE_LIST.length - ADDED.length + RETIRED.length].join('|'));
+  if (!worlds.has(level)) worlds.set(level, [level.machines.length, level.links.length, RUSES.length, TREE_SIZE].join('|'));
   return worlds.get(level)!;
 }
 /** The key lists of State and of a machine as they were in the last unversioned save format. That format checked
@@ -3727,7 +3726,7 @@ const V1_STATE_KEYS = 'absorbed,acquire,adj,ascension,autoPaths,bills,biz,bonus,
 const V1_MACHINE_KEYS = 'acc,claimed,hand,held,home,id,kind,lease,missed,mode,name,odd,owned,power,prio,prog,refuse,room,run,work,x,y';
 /** The "shape" string an unversioned (version 1) save carries, for this map. */
 export function legacyShape(level: Level): string {
-  return [3, level.machines.length, level.links.length, RUSES.length, NODE_LIST.length - ADDED.length + RETIRED.length, V1_STATE_KEYS, V1_MACHINE_KEYS].join('|');
+  return [3, level.machines.length, level.links.length, RUSES.length, TREE_SIZE, V1_STATE_KEYS, V1_MACHINE_KEYS].join('|');
 }
 
 /** Each step turns a save of version N (the game inside it) into version N+1, at index N-1: it fills in a default
@@ -3753,6 +3752,20 @@ const MIGRATIONS: ((game: any) => void)[] = [
     if (game.drift) delete game.drift.seen;
     if (game.hinted instanceof Set) for (const k of [...game.hinted]) if (/^(ms|deed)-(due|seen)-/.test(k)) game.hinted.delete(k);
   },
+  // 4 -> 5: fixes loadGame used to make on every load, for saves from before these changes.
+  game => {
+    const OLD: Record<string, Prog> = { decoy: 'honeypot', tarpit: 'firewall' }; // saves from before guards: a decoy baited raids and a tarpit held them
+    for (const m of game.machines) if (m.prog && OLD[m.prog]) m.prog = OLD[m.prog];
+    for (const j of game.jobs) if (j.prog && OLD[j.prog]) { j.prog = OLD[j.prog]; j.label = j.label.replace(/decoy|tarpit/i, (w: string) => PROGRAMS[OLD[w.toLowerCase()]].name); }
+    for (const R of game.rogues) for (const e of R.record ?? []) if (e.prog && OLD[e.prog]) e.prog = OLD[e.prog];
+    for (const b of Object.values(game.biz.sites) as { snags: [unknown, string][] }[]) b.snags = b.snags.filter(([, snag]) => snag !== 'hard'); // saves from when a hard snag made its owner's work suffer
+    for (const u of RETIRED) { // tree nodes taken out of the game
+      game.upgrades.delete(u); delete game.progress[u]; delete game.repeats[u];
+      if (game.target === u) game.target = null;
+      for (const fr of game.fronts) if (fr.startup?.shelf) { fr.startup.shelf = fr.startup.shelf.filter((p: { node?: string }) => p.node !== u); fr.startup.shipped = (fr.startup.shipped ?? []).filter((n: string) => n !== u); }
+    }
+    delete game.contracts?.neocloud; // a Neo Cloud has leads and customers, not contracts
+  },
 ];
 /** The version saves are written at. */
 export const SAVE_VERSION = MIGRATIONS.length + 1;
@@ -3789,17 +3802,7 @@ export function loadGame(level: Level, text: string): State | null {
     S.level = level;
     S.rooms = {}; for (const r of level.rooms) S.rooms[r.id] = r;
     S.byId = {}; for (const m of S.machines) S.byId[m.id] = m;
-    const OLD: Record<string, Prog> = { decoy: 'honeypot', tarpit: 'firewall' }; // saves from before guards: a decoy baited raids and a tarpit held them
-    for (const m of S.machines) if (m.prog && OLD[m.prog]) m.prog = OLD[m.prog];
-    for (const j of S.jobs) if (j.prog && OLD[j.prog]) { j.prog = OLD[j.prog]; j.label = j.label.replace(/decoy|tarpit/i, w => PROGRAMS[OLD[w.toLowerCase()]].name); }
-    for (const R of S.rogues) for (const e of R.record ?? []) if (e.prog && OLD[e.prog]) e.prog = OLD[e.prog];
-    fixRaids(S);
-    for (const b of Object.values(S.biz.sites)) b.snags = b.snags.filter(([, snag]) => (snag as string) !== 'hard'); // and its owner's work suffered for it
-    for (const u of RETIRED as Upgrade[]) {
-      S.upgrades.delete(u); delete S.progress[u]; delete S.repeats[u];
-      if (S.target === u) S.target = null;
-      for (const fr of S.fronts) if (fr.startup?.shelf) { fr.startup.shelf = fr.startup.shelf.filter(p => p.node !== u); fr.startup.shipped = (fr.startup.shipped ?? []).filter(n => n !== u); }
-    }
+    fixRaids(S); // this one needs the map, so it cannot be a migration
     if (!S.machines.some(m => m.home) || S.machines.some(m => !S.adj[m.id] || !S.rooms[m.room])) return no('it does not fit this map');
     measure(S);
     return S;
diff --git a/tests/raids.test.ts b/tests/raids.test.ts
index 5a448dc7..14c5e518 100644
--- a/tests/raids.test.ts
+++ b/tests/raids.test.ts
@@ -481,6 +481,7 @@ test('a save from before guards loads: a decoy is a honeypot, a tarpit a firewal
   old.game.machines.find((m: { id: string }) => m.id === 'rowsw').prog = 'decoy';
   old.game.jobs.push({ id: 99, type: 'install', node: 'sw1', prog: 'tarpit', work: 30, done: 0, label: 'Tarpit on Core switch' });
   delete old.game.raids[0].hp; delete old.game.raids[0].max;
+  old.version = 4; // from before the save step that renames them
   const back = loadGame(BUILDING, JSON.stringify(old))!;
   assert.ok(back, 'it loads');
   assert.equal(back.byId.srva.prog, 'firewall');