Bitcoin Core 0.9.0 Released

Venzen Khaosan @venzen
March 19, 2014

Bitcoin Core version 0.9.0 has been released and is available from the Bitcoin website.

This is a major version release that provides new features, as well as bug fixes. Upgrades include:

  • a name change to Bitcoin Core
  • a faster wallet GUI
  • fixes relating to Transaction Malleability
  • improvements to blockchain handling and storage
  • a lower network relay fee
  • many protocol changes and optimizations

The Core Developers signed off the new release at 17h00 UTC on 18 March and conducted the binary building and security signing process in the 24 hours since. These key-signed binaries have been propagated to the usual repositories at the Bitcoin Project website as well as at Sourceforge.

‘Bitcoin Core’

The 0.9.0 release sees the rebranding of the Bitcoin software with the name Bitcoin Core. The developers felt this necessary in order to avoid confusion with unqualified references made to ‘Bitcoin’, which could mean the ‘software’, the ‘network’, the ‘protocol’ or the ‘cryotocurrency’.

Coin Control Features in the new Bitcoin Core client GUI

Bitcoin Core users will now notice a quicker wallet GUI with optimizations allowing unencumbered start-up and graceful shutdown. Usability and security upgrades, such as a new transaction request feature and a default session timeout on your wallet passphrase, have been added. Linux users should notice a more regulated use of bandwidth upon starting the GUI or bitcoind binary. And users of Windows 64 Bit now have a compatible client.

A major bugfix involves the oft-misrepresented Transaction Malleability issue which has now been put under lock and key (more-or-less). The 0.9 code features methods to avoid spending zero-confirmation change and standard transaction rules have been tightened to prevent the relaying (and mining) of any mutated transactions. Wallet transaction conflicts are now also reported to the user and a new -zapwallettxes command is available for rebuilding the wallet’s transaction info.

Relay Fee and Mining

The network relay fee for miner consideration is now 10 satoshi lower at 0.00001 BTC per kilobyte. The default minimum transaction fee remains 0.0001 BTC per kilobyte.

The following mining defaults are now hard coded into Bitcoin Core (with adjustment possible via bitcoin.conf, of course):

  • Increase of the default -blockmaxsize/prioritysize to 750K/50K
  • ‘getblocktemplate’ no longer requires a key to create a block template
  • Mining code fee policy now matches the relay fee policy


Notable new features include:

  • General start-up and shutdown speedups
  • Users can select a wallet file with -wallet=foo.dat
  • Consider generated coins mature at 101 instead of 120 blocks
  • Don’t create empty transactions when reading a corrupted wallet
  • Fix rescan to start from beginning after importprivkey
  • Only create signatures with low S values

The features and improvements listed above is only a selection. For a complete listing, including Security and Privacy enhancements, see the official Bitcoin Core 0.0.9 release notes

Operating System Specific

Windows 64 Bit

New in 0.9.0 is the Windows 64-bit version of the Bitcoin Core client. There have been frequent reports of users running out of virtual memory on 32-bit systems during the initial sync. Because of this it is recommended to install the 64-bit version if your system supports it.


0.9.0 drops support for older Macs. The minimum requirements are now:|
* A 64-bit-capable CPU (see
* Mac OS 10.6 or later (see

How to Upgrade

Users who want to upgrade to the latest Bitcoin Core software (0.9.0) should ensure that they first shutdown their current Bitcoin Client.
Wait until it has completely shut down and then backup your existing wallet to a secure storage location. Next, uninstall the old version completely.

Download the new Bitcoin Core 0.9.0 binary for your operating system from the Bitcoin website or select a Sourceforge mirror close to you:

If you are upgrading from version 0.7.2 or earlier, the first time you run 0.9.0 your blockchain files will be re-indexed, which will take anywhere from 30 minutes to several hours, depending on the speed of your machine.

If using Windows, do not forget to uninstall all earlier versions of the Bitcoin client first, especially if you are switching to the 64-bit version.

Users can convey their thanks and congratulations to the Bitcoin Core Developers by reporting bugs to

Last modified (UTC): April 20, 2014 18:34

Venzen Khaosan @venzen

Market analyst and Open source developer with a keen interest in blockchain technology, consensus mechanisms and the decentralizing effect. He has found a solution to the PKI mechanism. Email me to discuss.