diff --git a/src/core/store/serialize.ts b/src/core/store/serialize.ts
index d7738acd..4b1c1edd 100644
--- a/src/core/store/serialize.ts
+++ b/src/core/store/serialize.ts
@@ -28,7 +28,7 @@ import type {
   TilemapLayer,
 } from '../model/Asset';
 import { parseCellKey } from '../model/tilemap';
-import { decodeCells, encodeCells, isStoredCells } from './tilemapCells';
+import { decodeCells, encodeCells } from './tilemapCells';
 import { isAssetType } from '../model/AssetTypes';
 import { isFontFile } from '../model/font';
 import { isSoundFile } from '../model/sound';
@@ -80,7 +80,7 @@ import { SHADER_KEY, shaderParamDefs } from '../properties/shaders';
  */
 export function deserializeProject(raw: unknown, fallbackId = ''): Project {
   const r = asRecord(raw);
-  const rawAssets = (Array.isArray(r.assets) ? r.assets : []).map(asRecord).map(migrateAsset);
+  const rawAssets = (Array.isArray(r.assets) ? r.assets : []).map(asRecord);
 
   // Pass 1: asset ids and their effective schemas, needed to coerce overrides in pass 2.
   const schemas = new Map<string, PropertySchema>();
@@ -524,8 +524,7 @@ function normalizeLayers(raw: unknown): TilemapLayer[] {
   for (const item of Array.isArray(raw) ? raw : []) {
     const l = asRecord(item);
     if (typeof l.id !== 'string' || !l.id || layers.some((o) => o.id === l.id)) continue;
-    // Projects saved before #134 hold the map itself; it is taken over as it is.
-    const stored = isStoredCells(l) ? decodeCells(l) : asRecord(l.cells);
+    const stored = decodeCells(l);
     const cells: Record<string, string> = {};
     for (const [key, value] of Object.entries(stored))
       if (parseCellKey(key) && typeof value === 'string' && value !== '') cells[key] = value;
@@ -550,17 +549,6 @@ function normalizeBag(raw: unknown, schema: PropertySchema, sparse: boolean): Pr
   return bag;
 }
 
-/**
- * A tile was called an autotile before it could be a plain one (#131). Such an asset had no kind
- * but the autotile blocks, and one written without a kind meant a floor – which it has to stay now
- * that a missing kind means a plain tile.
- */
-function migrateAsset(a: Record<string, unknown>): Record<string, unknown> {
-  if (a.type !== 'autotile') return a;
-  const props = asRecord(a.props);
-  return { ...a, type: 'tile', props: { ...props, kind: props.kind ?? 'floor' } };
-}
-
 function asRecord(value: unknown): Record<string, unknown> {
   return value && typeof value === 'object' ? (value as Record<string, unknown>) : {};
 }
diff --git a/src/core/store/tilemapCells.ts b/src/core/store/tilemapCells.ts
index 1719723f..3f01e3ae 100644
--- a/src/core/store/tilemapCells.ts
+++ b/src/core/store/tilemapCells.ts
@@ -113,8 +113,3 @@ export function decodeCells(raw: {
   });
   return cells;
 }
-
-/** Whether a stored layer is in this format rather than the map of the first version (#128). */
-export function isStoredCells(raw: Record<string, unknown>): boolean {
-  return Array.isArray(raw.rows);
-}
diff --git a/tests/core/tile.test.ts b/tests/core/tile.test.ts
index a66b2f70..83c27c80 100644
--- a/tests/core/tile.test.ts
+++ b/tests/core/tile.test.ts
@@ -417,29 +417,17 @@ describe('tile in the document', () => {
     expect(tilePlayback(read)).toBe('loop');
   });
 
-  /**
-   * #131 renamed the asset and made a plain tile the default. A project saved before that holds
-   * `autotile` assets, and one of them without a stored kind meant a floor block: it has to open as
-   * the same floor, not turn into a plain tile.
-   */
-  it('reads an autotile of an older project as the tile it was', () => {
+  // No migration any more (#137): `autotile`, the name before #131, is an unknown type like any other.
+  it('drops an asset of the old type autotile', () => {
     const raw = {
       id: 'p',
       assets: [
         { id: 's', type: 'scene', name: 'Main', props: {}, objects: [] },
-        { id: 'a', type: 'autotile', name: 'Old grass', props: {}, pictures: ['x'] },
-        { id: 'b', type: 'autotile', name: 'Old wall', props: { kind: 'wall', fps: 2 }, pictures: [] },
+        { id: 'a', type: 'autotile', name: 'Old grass', props: { kind: 'floor' }, pictures: ['x'] },
         { id: 'c', type: 'tile', name: 'New', props: {}, pictures: [] },
       ],
     };
-    const project = deserializeProject(raw);
-    const byId = (id: string) => project.assets.find((a): a is TileAsset => a.id === id && a.type === 'tile');
-    expect(byId('a')?.pictures).toEqual(['x']);
-    expect(tileKind(byId('a')!)).toBe('floor');
-    expect(tileKind(byId('b')!)).toBe('wall');
-    expect(byId('b')?.props.fps).toBe(2);
-    expect(tileKind(byId('c')!)).toBe('none');
-    expect(project.assets.some((a) => (a.type as string) === 'autotile')).toBe(false);
+    expect(deserializeProject(raw).assets.map((a) => a.id)).toEqual(['s', 'c']);
   });
 });
 
diff --git a/tests/core/tilemap-cells.test.ts b/tests/core/tilemap-cells.test.ts
index 5316d765..1dae7192 100644
--- a/tests/core/tilemap-cells.test.ts
+++ b/tests/core/tilemap-cells.test.ts
@@ -108,19 +108,14 @@ describe('the cells of a tilemap in the file', () => {
     expect((findAsset(project, id) as TilemapAsset).layers[0]!.cells).toEqual(cells);
   });
 
-  it('take a project saved before #134 over as it is, and write it in the new form', () => {
+  // No migration any more (#137): the map of the first version (#128) is not read.
+  it('read a layer holding the map itself as empty', () => {
     const { project, id } = projectWith({});
     const raw = serializeProject(project) as { assets: Record<string, unknown>[] };
-    const old = raw.assets.find((a) => a.id === id)!;
-    old.layers = [
-      { id: 'L1', name: 'Ground', cells: { '1,2': 'grass', '2,2': 'grass', nonsense: 'x', '3,3': '' } },
-    ];
-    const loaded = deserializeProject(raw);
-    expect((findAsset(loaded, id) as TilemapAsset).layers[0]!.cells).toEqual({
-      '1,2': 'grass',
-      '2,2': 'grass',
-    });
-    expect(storedLayer(serializeProject(loaded), id)).toMatchObject({ tiles: ['grass'], rows: ['1*2'] });
+    raw.assets.find((a) => a.id === id)!.layers = [{ id: 'L1', name: 'Ground', cells: { '1,2': 'grass' } }];
+    const layer = (findAsset(deserializeProject(raw), id) as TilemapAsset).layers[0]!;
+    expect(layer).toMatchObject({ id: 'L1', name: 'Ground' });
+    expect(layer.cells).toEqual({});
   });
 
   it('shrink a full map of 100 × 100 with two layers to a small part of the old size', () => {