Don't make people read the same thing twice

Author: vweevers

UPGRADING.md

@@ -4,42 +4,15 @@ This document describes breaking changes and how to upgrade. For a complete list
 
 ## 10.0.0
 
-This release upgrades to `abstract-level` 3. Please see its [upgrade guide](https://github.com/Level/abstract-level/blob/v3.0.0/UPGRADING.md) for details. On this end we'll only summarize its new features, because they're not supported in all environments.
+This release upgrades to `abstract-level` 3. Please see its [upgrade guide](https://github.com/Level/abstract-level/blob/v3.0.0/UPGRADING.md).
 
-In Node.js (but not browsers) you can now create "explicit snapshots" to read previous versions of a database:
-
-```js
-await db.put('example', 'before')
-const snapshot = db.snapshot()
-await db.put('example', 'after')
-await db.get('example', { snapshot })) // Returns 'before'
-await snapshot.close()
-```
-
-In Node.js with TypeScript (5.2) that last `close()` call can be skipped because we added support of [`Symbol.asyncDispose`](https://github.com/tc39/proposal-explicit-resource-management) on databases, iterators and snapshots:
-
-```ts
-await db.put('example', 'before')
-await using snapshot = db.snapshot()
-await db.put('example', 'after')
-await db.get('example', { snapshot })) // Returns 'before'
-```
-
-In Node.js and browsers you can use newly-added `has()` and `hasMany()` methods to check if keys exist without the cost of fetching values:
-
-```js
-if (await db.has('fruit')) {
-  console.log('We have fruit')
-}
-```
-
-In Node.js you can (in certain cases) improve application performance using a new `getSync()` method that blocks the event loop but can be significantly faster than the asynchronous `db.get()` method:
+Not mentioned in that guide is the later addition of `db.getSync()`. This new method blocks the event loop but can be significantly faster than `db.get()`:
 
 ```js
 const value = db.getSync('example')
 ```
 
-Lastly, `has()`, `hasMany()` and `getSync()` also support explicit snapshots. Bon appétit!
+It is only supported in Node.js (via `classic-level`) and not in browsers.
 
 ## 9.0.0