* Recent versions of Linux / FreeBSD are required for AirPlay 2 operation. At the time of writing, May 2, 2021, everything is on the latest version of the software -- macOS 11.3, iOS 14.5, Raspberry Pi OS 5.10.17-v7l+ (Buster), FreeBSD 12.1, Ubuntu 18.04 -- fully updated. A further requirement is an AAC decoder capable of decoding Planar Floating Point `"fltp"` material. Unfortuately, some prominent Linux distributions -- notably Fedora 36 -- do not include this decoder. See [here](https://github.com/mikebrady/shairport-sync/blob/development/TROUBLESHOOTING.md#aac-decoder-issues-airplay-2-only) for more on this.
* Be very careful with audio systems capable of very high volume output -- the volume control in this software may not be reliable!
* Shairport Sync relies on a companion program called [`nqptp`](https://github.com/mikebrady/nqptp) to monitor timing signals. This program uses ports 319 and 320 and replaces any PTP service you have on the computer.
- (FYI, most computers do not have a PTP clock running. They often use a (totally different) [Network Timing Protocol (NTP)](http://www.ntp.org) service to keep the system clock synchronised with world time.) The POSIX Shared Memory Interface (SMI) Version numbers of `nqptp` and Shairport Sync must match. If they don't, you'll get a message in the logs. It means that one of the programs is out of date with respect to the other.
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+ FYI, most computers do not have a PTP service running. They often use a (totally different) [Network Timing Protocol (NTP)](http://www.ntp.org) service to keep the system clock synchronised with civil time. The POSIX Shared Memory Interface (SMI) Version numbers of `nqptp` and Shairport Sync must match. If they don't, you'll get a message in the logs. It means that one of the programs is out of date with respect to the other.
Instructions
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