# 8.x → 9.0.0, entry by entry

**Five breaking entries, from closing the ten findings the 8.0.0 sweep filed rather than absorbed.**
Four are compile errors the moment you upgrade. The fifth changes what your cache ladder *is*, at
runtime, and it is the one to read even if nothing else here applies. No codemod.

| # | Surface | Costs you an edit if |
|---|---|---|
| 1 | `@ultimat3/render` splits into `.` and `./server` | you import a build-time name, or relied on importing the barrel to install the `.tsx` loader |
| 2 | `cache.tiers` names the ladder's own rungs, and is now read | your `app.config.ts` sets `cache.tiers` — **runtime behaviour changes even if it compiles** |
| 3 | `@ultimat3/storage` renames `IMAGE_FORMATS` / `ImageFormat` | you imported either |
| 4 | `@ultimat3/pwa` drops the forced-reload half of `version-skew` | you called `updateSignal` or `updatePolicy` |
| 5 | `@ultimat3/core` replaces `CacheTier` with `CacheTierName` | you named the type |

### 1. `@ultimat3/render` splits into `.` and `./server`

```diff
- import { defineRoute, renderToHtml } from '@ultimat3/render';
+ import { defineRoute } from '@ultimat3/render';
+ import { renderToHtml } from '@ultimat3/render/server';
```

55 names moved: the render pipeline (`renderToHtml`, `renderSsr`, `renderStatic`, `renderStreamHtml`,
the ISR controller) and the loaders (`installRenderLoader`, `compileStylesheet`, `stylesFor`,
`transformTsx`). `.` keeps the authoring vocabulary — `defineRoute`, `h`, `Fragment`, `island`,
`hydrate*`, the registry, the mode tables.

**Second, easily-missed half: importing `@ultimat3/render` no longer installs the `.tsx`/`.scss`
loader.** `@ultimat3/render/server` does. A test that did `await import('@ultimat3/render')` before
loading a page module must now import `/server`.

Why: `bun build --target=browser` on the barrel failed outright — *"Browser polyfill for module
`node:url` doesn't have a matching export named `fileURLToPath`"*, out of `css-modules.ts`. The
island this framework tells you to write could not be bundled.

### 2. `cache.tiers` names the ladder's rungs, and the ladder is now that declaration

```diff
- cache: { tiers: ['memo', 'lru', 'shared', 'isr'] }
+ cache: { tiers: ['request-memo', 'lru', 'redis'] }
```

`memo` → `request-memo`, `shared` → `redis`, and **delete `isr`** — it is a `RenderMode`, and the
routes that want it declare `render: 'isr'`. It named a cache rung that never existed.

**Read this even if your config already compiles.** The key was previously read by *nothing*:
`startCacheTiers` registered memo + lru unconditionally, redis on `REDIS_URL`, cdn on a purge
credential. An app declaring `tiers: ['request-memo']` measurably got
`['request-memo', 'lru', 'redis', 'cdn']`. Now the ladder is the declaration, which means:

- naming a rung the environment cannot supply **refuses the boot** — `redis` without `REDIS_URL`,
  `cdn` without a purge credential — rather than quietly building a shorter ladder
- an environment offering a rung the config does not name logs `cache.tier.unnamed` and builds nothing

If you relied on the old always-on `lru`, or on `REDIS_URL` adding a tier your config never
mentioned, **name it**.

### 3. `@ultimat3/storage` renames its image vocabulary

```diff
- import { IMAGE_FORMATS, type ImageFormat } from '@ultimat3/storage';
+ import { VARIANT_FORMATS, type VariantFormat } from '@ultimat3/storage';
```

Both packages exported those two names over **different sets**, so a storage caller narrowing on
storage's type had a type saying `gif` cannot occur and a value from core's probe that was one. If
you were probing rather than minting variants, the six-format set is `IMAGE_FORMATS` from
`@ultimat3/core` — which is what you actually had.

`variantKey()` also now refuses a format outside `VARIANT_FORMATS` instead of returning a key ending
`.undefined`.

### 4. `@ultimat3/pwa` drops the forced-reload half of `version-skew`

Removed: `updateSignal`, `updatePolicy`, `DEFAULT_GRACE_MS`, and the types `ForceReason`,
`UpdatePolicy`, `UpdatePolicyInput`, `UpdateSignalInput`. `AppUpdateAvailable` narrows to
`{ type, to }`, losing `from`, `forced` and `deadlineAt`.

Nothing performed the reload they described, and no runtime could have called them: `@ultimat3/http`
(tier 2) and `@ultimat3/realtime` (tier 3) both sit *below* `pwa` (tier 4). **Forcing a reload is not
a capability this framework has.** Notification is, and is complete — read
`useConnection().updateAvailable`, or compare the worker's posted `to` with `detectSkew`, and render
your own affordance.

### 5. `CacheTier` → `CacheTierName` in `@ultimat3/core`

The type behind entry 2. `@ultimat3/cache` still exports a `CacheTier` — it is the tier *interface*,
a different thing, and it is unchanged. The two sharing one name is what made a type error about
`CacheTier` unreadable.