> ## Documentation Index
> Fetch the complete documentation index at: https://whatsapp-rust.jlucaso.com/llms.txt
> Use this file to discover all available pages before exploring further.

# September 23, 2026 — Read server A/B props from your app

> Register extra A/B props on the builder and read them back as Option<bool> to gate application behavior on WhatsApp server flags.

## Features

**Public A/B props read API ([#1539](https://github.com/oxidezap/whatsapp-rust/pull/1539))**

Applications can now watch and read boolean A/B props the library doesn't already consume, so a server gate like `AURA_PINNED_CHATS_BENEFIT_ACTIVE` (the WhatsApp Plus pinned-chats limit) is reachable from user code.

Previously the props cache kept only flags in the library's internal `WATCHED` set and dropped everything else while the catalog streamed in, so an application had no way to learn a server gate it cared about.

New builder methods and client accessor:

* [`ClientBuilder::with_watched_ab_props`](/api/client#watching-additional-flags) and [`BotBuilder::with_watched_ab_props`](/api/bot#with_watched_ab_props) register extra `AbProp` flags before the first `fetch_props()`. Calls accumulate.
* [`Client::ab_prop_enabled`](/api/client#ab_prop_enabled) reads a watched boolean prop back as `Option<bool>`. It returns `None` when the client holds no value — not watched, not fetched yet, or not sent by the server — instead of substituting the registry default, so callers can tell "off" from "unknown".

```rust theme={null}
use wacore::iq::abprops::web::AURA_PINNED_CHATS_BENEFIT_ACTIVE;

let bot = Bot::builder()
    .with_watched_ab_props([AURA_PINNED_CHATS_BENEFIT_ACTIVE])
    // ...
    .build()
    .await?;

match bot
    .client()
    .ab_prop_enabled(AURA_PINNED_CHATS_BENEFIT_ACTIVE)
    .await
{
    Some(true) => enable_extended_pinned_chats(),
    Some(false) => enforce_default_pinned_chats_limit(),
    None => wait_for_next_fetch(),
}
```

The cache exposes the underlying truthy parsing as [`AbPropsCache::get_bool`](/api/client#ab-props-cache), which `is_enabled` now reuses so both paths agree on what counts as `"1"`, `"true"`, or `"enabled"`.