release notes 0.18

release_notes/changelog-0.18.md

@@ -0,0 +1,69 @@
+What's New in 0.18
+==================
+
+Release 0.18 brings several major improvements to Blockstack Core.  It is not a
+consensus-breaking release.  0.18.x nodes will continue to agree with 0.17.x
+nodes about the chain state.
+
+However, 0.18 is a **network-breaking release**.  In 0.18, a zone file can be
+40kb, which is 10x larger than the maximum zone file size in 0.17.  Large zone
+files announced to 0.18 will not be discovered by 0.17 nodes.  As such, all node
+operators are encouraged to upgrade to 0.18 as soon as possible.
+
+Release Highlights
+------------------
+
+**Server-side Subdomain Indexing**:  This release makes it so the
+`blockstack-core` daemon eagerly indexes subdomain records found in zone files.
+Name lookups and address lookups will return information for subdomains as well
+as names.  The `blockstack_client` library will no longer be responsible for
+maintaining subdomain state of its own.
+
+**Any Name can Update a Subdomain**:  Any name can send out a subdomain update
+record for a given subdomain.  It is no longer limited to the name that created
+it.  However, subdomain transfers must be processed by the name that created
+them for the time being.
+
+**10x Zone File Size Increase**:  The 0.18 Atlas network allows a maximum zone
+file size of 40kb.  This allows between 100 and 120 subdomains to be created in
+a single transaction.
+
+**New Subdomain Registrar**:  This version of the software ships with a new
+subdomain registrar designed to take advantage of the above.
+
+**Legacy Python Storage API Deprecation**:  This release deprecates the `/v1/store` API routes
+in `blockstack api` in favor of Gaia hubs.  Gaia hubs are accessed directly by
+`blockstack.js` via HTTP(S), and employ storage drivers to
+communicate with non-HTTP data sources.  This was introduced in 0.16, and going
+forward, will be the only supported way for reading and writing Blockstack app data.
+The legacy Python API will be removed in the next release.
+
+**Improved chain-state database**:  The
+[virtualchain](https://github.com/blockstack/virtualchain) package has changed
+the way it represents its consensus hashes and accepted transactions on disk.
+The changes make certain queries much more efficient, such as name history
+queries.  In addition, it makes block processing somewhat faster, and makes it
+easier to add more opcodes in a future release.  It removes a lot of complexity
+from Blockstack Core's consensus code.
+
+Getting Started
+---------------
+
+The recommended way to get started with 0.18 is through its fast-sync mode.  To
+migrate from a 0.17 node to a 0.18 node, we recommend the following steps:
+
+```
+# stop the old node
+$ blockstack-core stop
+$ mv ~/.blockstack-server ~/.blockstack-server.0.17
+
+# start the new node
+$ blockstack-core fast-sync
+$ blockstack-core start
+```
+
+The old chain state database directory structure has changed, and is 
+incompatible with this new release.  If you are
+upgrading from a 0.17 node or older, you will need to remove your `.blockstack-server`
+directory.
+