Update required C++ standard to C++20 for Social SDK 1.9 (#8365)

* Update required C++ standard to C++20 for Social SDK 1.9

The Standalone C++ getting-started guide stated C++17 as the minimum,
but as of SDK 1.9 the default target is C++20 on all platforms except
PlayStation 4 / PS5 with SDK older than 13.000, which still uses C++17.
Updates the prereq bullet, the CMakeLists.txt starter snippet, and adds
an Info callout flagging the PS exception.

* Add Game Engine and Language section to Platform Compatibility

Documents minimum supported versions for Standalone C++ (C++20), Unity
(2021.3), and Unreal Engine (5.5), with callouts for the PS4/PS5 C++17
carve-out and the pre-1.9 C++17 minimum. Removes the duplicate PS
callout from the C++ getting-started guide now that it lives in the
shared Platform Compatibility page.

Author: markmandel

developers/discord-social-sdk/core-concepts/platform-compatibility.mdx

@@ -9,6 +9,31 @@ import SonyCallout from '/snippets/discord-social-sdk/callouts/sony.mdx';
 You can find instructions on how to download the SDK for each platform in the [Getting Started](/developers/discord-social-sdk/getting-started) guide.
 </Info>
 
+---
+
+## Game Engine and Language
+
+The Discord Social SDK supports the following game engines and language environments:
+
+| Integration    | Minimum Supported Version |
+|----------------|---------------------------|
+| Standalone C++ | C++20                     |
+| Unity          | 2021.3                    |
+| Unreal Engine  | 5.5                       |
+
+<Info>
+    **PlayStation 4 / PS5 exception:** If you're targeting PlayStation 4, or PlayStation 5 with a PS5 SDK older than
+    13.000, the Discord Social SDK still supports C++17. All other platforms require C++20.
+</Info>
+
+<Info>
+    Prior to Social SDK release 1.9, C++17 is the minimum supported version.
+</Info>
+
+---
+
+## Platforms
+
 The Discord Social SDK is available for the following platforms:
 
 | Platform         | Minimum Supported Version | Support Level       | Standalone C++ | Unreal Engine | Unity |
@@ -62,6 +87,7 @@ Configure authentication, explore features, and get started with setup:
 
 ## Change Log
 
-| Date          | Changes         |
-|---------------|-----------------|
-| July 21, 2025 | initial release |
+| Date          | Changes                                 |
+|---------------|-----------------------------------------|
+| May 20, 2026  | Added Game Engine and Language section. |
+| July 21, 2025 | initial release                         |

developers/discord-social-sdk/getting-started/using-c++.mdx

@@ -23,7 +23,7 @@ This guide will walk you through integrating the Discord Social SDK into a new s
 We are going to make a simple C++ console application for this guide. Make sure you have the following prerequisites:
 
 - Basic understanding of C++ and your platform's build system
-- C++ Compiler and Build System that supports [C++17](https://en.cppreference.com/w/cpp/17) or greater.
+- C++ Compiler and Build System that supports [C++20](https://en.cppreference.com/w/cpp/20) or greater.
 - A network connection that can access Discord's API endpoints.
 
 Let's walk through the steps in detail.
@@ -85,7 +85,7 @@ Add the following contents to the `CMakeLists.txt` file to set up the Social SDK
 cmake_minimum_required(VERSION 3.10)
 project(DiscordSDKExample)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 
 add_executable(DiscordSDKExample main.cpp)
@@ -972,9 +972,10 @@ import {InboxIcon} from '/snippets/icons/InboxIcon.jsx'
 
 ## Change Log
 
-| Date           | Changes         |
-|----------------|-----------------|
-| March 17, 2025 | initial release |
+| Date           | Changes                                                 |
+|----------------|---------------------------------------------------------|
+| May 20, 2026   | Updated required C++ standard to C++20 with 1.9 release |
+| March 17, 2025 | initial release                                         |
 
 {/* Autogenerated Reference Links */}
 [`Activity`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Activity.html#ae793d9adbe16fef402b859ba02bee682
@@ -984,4 +985,4 @@ import {InboxIcon} from '/snippets/icons/InboxIcon.jsx'
 [`Client::GetDefaultPresenceScopes`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a7648bd1d2f7d9a86ebd0edb8bef12b5c
 [`Client::GetRelationships`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#ad481849835cd570f0e03adafcf90125d
 [`Client::UpdateToken`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a606b32cef7796f7fb91c2497bc31afc4
-[`RunCallbacks`]: https://discord.com/developers/docs/social-sdk/namespacediscordpp.html#ab5dd8cf274f581ee1885de5816be3c29
+[`RunCallbacks`]: https://discord.com/developers/docs/social-sdk/namespacediscordpp.html#ab5dd8cf274f581ee1885de5816be3c29