docs: Add deprecation notes

Author: ZPascal

README.md

@@ -17,6 +17,41 @@ The `cf-java-client` project is a Java language binding for interacting with a C
 ## Versions
 The Cloud Foundry Java Client has two active versions. The `5.x` line is compatible with Spring Boot `2.4.x - 2.6.x` just to manage its dependencies, while the `4.x` line uses Spring Boot `2.3.x`.
 
+## Deprecations
+
+### `DopplerClient.recentLogs()` — Recent Logs via Doppler
+
+> [!WARNING]
+> **Deprecated since cf-java-client `5.17.x`**
+>
+> The `DopplerClient.recentLogs()` endpoint (and the related `RecentLogsRequest` / `LogMessage` types from the `org.cloudfoundry.doppler` package) are **deprecated** and will be removed in a future release.
+>
+> This API relies on the [Loggregator][loggregator] Doppler/Traffic Controller endpoint `/apps/{id}/recentlogs`, which was removed in **Loggregator ≥ 107.0**.
+> The affected platform versions are:
+>
+> | Platform | Last version with Doppler recent-logs support |
+> | -------- | --------------------------------------------- |
+> | CF Deployment (CFD) | `< 24.3` |
+> | Tanzu Application Service (TAS) | `< 4.0` |
+>
+> **Migration:** Replace any call to `DopplerClient.recentLogs()` with [`LogCacheClient.read()`][log-cache-api] (available via `org.cloudfoundry.logcache.v1.LogCacheClient`).
+>
+> ```java
+> // Before (deprecated)
+> dopplerClient.recentLogs(RecentLogsRequest.builder()
+>     .applicationId(appId)
+>     .build());
+>
+> // After
+> logCacheClient.read(ReadRequest.builder()
+>     .sourceId(appId)
+>     .envelopeTypes(EnvelopeType.LOG)
+>     .build());
+> ```
+
+[loggregator]: https://github.com/cloudfoundry/loggregator
+[log-cache-api]: https://github.com/cloudfoundry/log-cache
+
 ## Dependencies
 Most projects will need two dependencies; the Operations API and an implementation of the Client API.  For Maven, the dependencies would be defined like this:
 
@@ -76,6 +111,9 @@ Both the `cloudfoundry-operations` and `cloudfoundry-client` projects follow a [
 
 ### `CloudFoundryClient`, `DopplerClient`, `UaaClient` Builders
 
+> [!NOTE]
+> **`DopplerClient` — partial deprecation:** The `recentLogs()` method on `DopplerClient` is deprecated and only works against Loggregator \< 107.0 (CFD \< 24.3 / TAS \< 4.0). See the [Deprecations](#deprecations) section above for the migration path to `LogCacheClient`.
+
 The lowest-level building blocks of the API are `ConnectionContext` and `TokenProvider`.  These types are intended to be shared between instances of the clients, and come with out of the box implementations.  To instantiate them, you configure them with builders:
 
 ```java