---
layout: post
title: Monero 0.9.0 "Hydrogen Helix" Released
summary: A major release in Monero's history, too much to summarise!
tags: [releases]
author: Riccardo Spagni (fluffypony)
---

*January 1st, 2016*

## Summary of Changes

Too much to describe. Represents a major release in Monero's history, over a year-and-a-half in the making. Some highlights:

- moved from in-RAM database to a backend-agnostic blockchain database
- created an LMDB blockchainDB implementation (with the help of Howard Chu, the creator of LMDB)
- created a BerkeleyDB blockchainDB implementation
- created an OS-agnostic raw blockchain format
- built tools to convert between blockchain implementations, as well as import and export them
- added ARM support
- brought back 32-bit support (WIP)
- added QoS (bandwidth control)
- added [OpenAlias](https://openalias.org) support
- fixed all (previously broken) unit tests and core tests
- implemented daemonize for proper backgrounding of the Monero daemon
- drastically increased sync speed
- included block headers in the source
- designed and implemented a stealth payment ID scheme
- designed and implemented a unified address+payment ID scheme
- implemented a hard fork mechanism
- changed the block time to 2 minutes
- implemented the [MRL-0001](https://lab.getmonero.org/pubs/MRL-0001.pdf) and [MRL-0004](https://lab.getmonero.org/pubs/MRL-0004.pdf) recommendations
- added tons of simplewallet / rpcwallet / daemon commands
- added a dust handler to simplewallet
- created a multilanguage mechanism, implemented in simplewallet
- bug fixes, bug fixes, bug fixes
- completely overhauled the CMake (with the help of Kitware, the creators of CMake)
- added a bad peer auto-banning mechanism
- refactored a ton of code, added a ton of comments
- added a core crypto implementation based on SUPERCOP ref10
- switched to a triangular distribution for output selection
- added multiple new mnemonic wordlists, including Russian and Italian
- created a "trusted daemon" system for remote daemon use

In total this represents 922 commits worth of work by 9 contributors. This will probably be the biggest release in Monero's history, everything from here on out can be done as faster point releases.

## Updating: Blockchain Conversion

It is highly recommended that you delete the contents of your Monero working directory and sync from scratch. This directory can be found in ```~/.bitmonero``` on Linux and OS X, and on Windows in ```\Users\username\AppData\Roaming\bitmonero``` or ```\ProgramData\bitmonero```.

Syncing from scratch is EXTREMELY fast in this version, pretty much at bittorrent speeds, and will leave you with a fully verified blockchain.

*Alternatively*: if you want to grab the bootstrap (NOTE: there is a new bootstrap format!) off the website then you can get it at https://downloads.getmonero.org/blockchain.raw - once downloaded you can import it with ```blockchain_import --input-file /path/to/your/download.raw```. If you're particularly brave you can pass the ```--verify 0``` flag to skip verification during import.

*If you REALLY want to convert your old blockchain*: you can either use the ```blockchain_converter``` tool, or you can use ```blockchain_export``` to create a blockchain.raw, followed by ```blockchain_import``` to import it into the new LMDB format.

## Official Download Links

- [Windows, 64-bit](https://downloads.getmonero.org/monero.win.x64.v0-9-0-0.zip)
- [OS X, 64-bit](https://downloads.getmonero.org/monero.mac.x64.v0-9-0-0.tar.bz2)
- [Linux, 64-bit](https://downloads.getmonero.org/monero.linux.x64.v0-9-0-0.tar.bz2)

## Download Hashes

If you would like to verify that you have downloaded the correct file, please use the following SHA256 hashes:

- monero.win.x64.v0-9-0-0.zip, c61284c4d5f78db2bc2072bef76f2b539293cca74bdd3fb9536a35ca54b4fd2e
- monero.linux.x64.v0-9-0-0.tar.bz2, 655875a899aded6d63f99c5dfea6a45b3e77533bb2173e63612646ec7ac97100
- monero.mac.x64.v0-9-0-0.tar.bz2, fce5140d9cb38d62ad1b9f1b0d06feaa209433f9ec542b8d368ef9e0da431b78