Bitcoin QT GitHub

Bitcoin Core version 0.9.0 is now available from:

This is a new major version release, bringing both new features and bug fixes.

Please report bugs using the issue tracker at github:

How to Upgrade

If you are running an older version‚ shut it down. Wait until it has completely shut down (which might take a few minutes for older versions)‚ uninstall all earlier versions of Bitcoin‚ then run the installer (on Windows) or just copy over ⁄Applications⁄Bitcoin-Qt (on Mac) or bitcoind⁄bitcoin–qt (on Linux).

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.

On Windows‚ do not forget to uninstall all earlier versions of the Bitcoin client first‚ especially if you are switching to the 64–bit version.

Windows 64–bit installer

New in 0.9.0 is the Windows 64-bit version of the 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.

NOTE: Release candidate 2 Windows binaries are not code–signed; use PGP and the SHA256SUMS.asc file to make sure your binaries are correct. In the final 0.9.0 release‚ Windows setup.exe binaries will be code–signed.

OSX 10.5 ⁄ 32-bit no longer supported

0.9.0 drops support for older Macs. The minimum requirements are now:

Downgrading warnings

The ‘chainstate’ for this release is not always compatible with previous releases‚ so if you run 0.9 and then decide to switch back to a 0.8.x release you might get a blockchain validation error when starting the old release (due to ‘pruned outputs’ being omitted from the index of unspent transaction outputs).

Running the old release with the –reindex option will rebuild the chainstate data structures and correct the problem.