Update RELEASENOTES-DEVELOPMENT.md

diff --git a/RELEASENOTES-DEVELOPMENT.md b/RELEASENOTES-DEVELOPMENT.md
index 870a2fea943f549c8dc0d54390f4e869f9c89bd5..5f73973d3b589da10b1dd9e2ec435cb9d0d80ab7 100644 (file)
--- a/RELEASENOTES-DEVELOPMENT.md
+++ b/RELEASENOTES-DEVELOPMENT.md
@@ -5,16 +5,10 @@ Big Update
 ----
 Version 4 brings limited AirPlay 2 functionality to Shairport Sync. 
 
-A major feature of Shairport Sync's AirPlay 2 support is Audio Synchronisation. This is achieved using an purpose-built passive [PTP](https://standards.ieee.org/standard/1588-2008.html) client called [`nqptp`](https://github.com/mikebrady/nqptp), which provides precise timing information that Shairport Sync uses to maintain tight synchronisation. (BTW, `nqptp` is not a "PTP slave". Instead, it passively monitors PTP traffic for  timing information.)
+For more information about AirPlay 2, including acknowledgements, please visit [AIRPLAY2.md].
 
-Acknowledgements
-----
-Much of Shairport Sync's AirPlay 2 functionality is based on ideas developed at the [openairplay airplay2-receiver]( https://github.com/openairplay/airplay2-receiver) repository.
-
-Big thanks are due to number of individuals made direct and valuable contributions to Shairport Sync:
-1. [ejurgensen](https://github.com/ejurgensen) contributed ideas and code. The `pair_ap` submodule and related code in `rtsp.c` is theirs.
-2. [JD Smith](https://github.com/jdtsmith) contributed ideas, comments and suggestions along with extensive and thorough testing.
-3. [Charles Omer](https://github.com/charlesomer) contributed ideas, comments, bug fixes and Docker automation (forthcoming).
+#### Known Issues
+- In the AirPlay 2 build, a crash can occur occasionally when the player is being selected. If you can get this to happen reliably, please let us know.
 
 Warning
 ----
@@ -22,53 +16,6 @@ Warning
 2. There is lots we don't know about AirPlay 2. This can result in incorrect behaviour. Watch out for very high volume levels, especially if you have a powerful audio system.
 3. This is a `development` branch and is probably more buggy than usual. Normal support will not be provided -- instead, we will be interested in bug reports that help improve the program. You need to be adept with Linux or FreeBSD to get involved.
 
-AirPlay 2 Overview
-----
-
-#### What Works
-- AirPlay 2 for iOS and Mac players.
-
-#### What Does Not Work
-- No AirPlay 2 for Windows iTunes
-- No integration with Siri or HomeKit
-- No Lossless or High Definition Lossless
-- No Remote Control
-- No Artwork in the Metadata
-
-#### What Partly Works
-- Incomplete functionality using AppleTV or HomePod as player.
-   A Shairport Sync player will work, but the selection button won't persist and the volume can't be set.
-
-#### Limitations
-- You can only run a single instance of Shairport Sync on a device.
-- The AirPlay 2 version of Shairport Sync will not run on macOS, since `nqptp` can not be installed on it.
-
-#### Known Issues
-- A crash can occur occasionally when a Shairport Sync player is being selected for output. If you can get this to happen reliably, please let us know.
-
-AirPlay 2 -- What You Need
----
-AirPlay 2 support needs a more powerful CPU for decoding and synchronisation and more memory for bigger buffers and larger libraries. Raspberry Pi OS and Ubuntu 20.04 on a VM have been used extensively in development, with Alpine Linux and FreeBSD 12.2 being used to a lesser extent.
-
-Here are some suggestions: 
-* Full access, including `root` privileges, to a system at least as powerful as a Raspberry Pi 3.
-* A fully up-to-date Linux. This is important, as some of the libraries must be the latest available.
-* An audio output, for example an `alsa` device (or `sndio` in FreeBSD). The `stdout` and `pipe` backends continue to work as before. Other backends have not been tested.
-
-Guides
----
-Instructions for building Shairport Sync are different for AirPlay 2 than for AirPlay 1 -- please follow them very carefully.
-
-* A brief guide to building Shairport Sync for AirPlay 1 is available at [BUILDFORAP1.md](https://github.com/aillwee/shairport-sync/blob/development/BUILDFORAP1.md).
-* To build Shairport Sync for AirPlay 2 on Linux, please follow the guide at [BUILDFORAP2.md](https://github.com/aillwee/shairport-sync/blob/development/BUILDFORAP2.md).
-* A guide for building on FreeBSD is forthcoming.
-
-AirPlay 2 -- More About What Works
----
-* Two types of audio are received -- "Realtime" streams of CD quality ALAC (like AirPlay 1) and "Buffered Audio" streams of AAC stereo at 44,100 frames per second. The selection of stream type is made by the player.
-* Audio is synchronised with other AirPlay 2 devices, including AirPlay 2 devices that have their own master clocks. (Note: This has not been tested with multiple nearly-identical master clock devices such as with two HomePod minis -- Shairport Sync will get confused about which is the current master.)
-* Shairport Sync continues to support AirPlay 1, and offers an AirPlay 1 compatibility mode for situations where iTunes on macOS or macOS Music plays to multiple speakers and one of more of them is compatible with AirPlay 1 only.
-
 Version 3.3.8d7
 ====
 **Bug Fix**