Add changelog for bitcoin-satellite 0.2.1

doc/release-notes/satellite/release-notes-0.2.1.md

@@ -0,0 +1,91 @@
+Bitcoin Satellite 0.2.1 Release Notes
+====================
+
+Bitcoin Satellite version 0.2.1 is now available for Ubuntu, Fedora, and CentOS
+at:
+
+  - [Launchpad (Debian packages)](https://launchpad.net/~blockstream/+archive/ubuntu/satellite)
+  - [Copr (RPM package)](https://copr.fedorainfracloud.org/coprs/blockstream/satellite/)
+
+This is a new minor version release including bug fixes.
+
+Please report bugs using the issue tracker:
+
+  <https://github.com/Blockstream/bitcoinsatellite/issues>
+
+Alternatively, contact us at:
+
+  - <https://help.blockstream.com/>
+  - #blockstream-satellite IRC channel on freenode
+
+How to Upgrade
+==============
+
+The easiest way to upgrade is by using the
+[`blocksat-cli`](https://github.com/Blockstream/satellite/blob/master/doc/quick-reference.md),
+the Blockstream Satellite command-line interface (CLI). Assuming you already
+have it installed, run:
+
+```
+blocksat-cli deps update --btc
+```
+
+Otherwise, you can [install the
+CLI](https://github.com/Blockstream/satellite/blob/master/doc/quick-reference.md#1-cli-installation-and-upgrade)
+and run the above command.
+
+Alternatively, you can upgrade Bitcoin Satellite manually by running the
+following commands:
+
+Ubuntu:
+```
+add-apt-repository ppa:blockstream/satellite
+apt-get update
+apt-get install --only-upgrade bitcoin-satellite
+```
+
+Fedora:
+```
+dnf copr enable blockstream/satellite
+dnf upgrade bitcoin-satellite
+```
+
+CentOS:
+```
+yum copr enable blockstream/satellite
+yum upgrade bitcoin-satellite
+```
+
+Compatibility
+==============
+
+Bitcoin Satellite is supported and tested on Linux distributions using the
+latest two Ubuntu LTS, Fedora, and CentOS releases.
+
+Bitcoin Core Version
+==============
+
+Bitcoin Satellite is a fork of Bitcoin Core. This specific Bitcoin Satellite
+release (version 0.2.1) is available in three package versions, over three
+distinct Bitcoin Core versions:
+
+- Bitcoin Core 0.21.1 (package version `0.21.1.0.2.1`).
+- Bitcoin Core 0.21.0 (package version `0.21.0.0.2.1`).
+- Bitcoin Core 0.19.1 (package version `0.19.1.0.2.1`).
+
+0.2.1 Changelog
+=================
+
+### FEC
+- Update the Wirehair and cm256 sources to their latest versions.
+- Fix fixture incompatibility and various other sources of instability on the
+  FEC unit tests.
+- Remove FEC test dependencies on Boost 1.61.
+- Move the FEC implementation to a dedicated static library and assign the
+  specific instruction subsets required to build it.
+- Fix compilation based on native architecture (`march=native`) used previously
+  to compile the FEC sources.
+
+### UDP Multicast Tx
+- Make ring buffer and throttle unit tests less prone to racing conditions.
+- Fix detection of full state on the ring buffer used for multicast Tx.