Add release notes for 0.5.7
# Release Notes
+## Changes in Splinter 0.5.7
+
+### Highlights
+
+* A new version of Trust Authorization has been added. The v0 had a race
+ condition that has now been fixed in the new version. It is currently behind
+ an experimental feature `trust-authorization`.
+
+### libsplinter
+
+* Implement v1 Trust Authorization. This version makes room for adding Challenge
+ Authorization as well as fixes a race condition present in v0 Trust
+ Authorization. If a `ConnectRequest` is the first message received v0 trust
+ will be used. If `AuthProtocolRequest` is the first message v1 Trust will be
+ used. This is required to stay backwards compatible with 0.4. v1 is behind an
+ experimental features `trust-authorization`
+
+* Update the `RefMap` to take a generic key. The RefMap is used to keep track of
+ peers to know when the connection should be dropped. With the addition of
+ challenge authorization the peer id is going to be updated to be an Enum
+ instead of a String, as such the reference map needs to be updated to take
+ keys that are other types.
+
+* Add a default for YamlCircuitStatus in the `YamlAdminServiceStore`. If a
+ circuit status is not in the yaml state, it defaults to Active. This is
+ required for backwards compatibility with 0.4.
+
+* Add authorization type and public keys to the `RoutingTable`. This information
+ is required for properly routing a message once Challenge Authorization is
+ implemented.
+
+* Update the handling of proposed circuits to check node IDs in the list of
+ proposed disband members to verify nodes that have previously peered still
+ have an agreed upon protocol version.
+
+### splinterd
+
+* Changed logging libraries to the more flexible log4rs to enable future logging
+ expansions.
+
+* Add a feature "deprecate-yaml" that deprecates yaml state in splinterd in
+ favor of using sqlite or postgresql. If splinterd is run with yaml state, it
+ will abort and point the user to the "splinter upgrade" command, which imports
+ the yaml state into the specified database.
+
+### splinter CLI
+
+* Add experimental feature `upgrade` to the splinter CLI. This command will port
+ YAML state files to database state.
+
## Changes in Splinter 0.5.6
### Highlights
