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Bitcoin-Qt 0.8.4

Bitcoin-Qt version 0.8.4 is now available from:

This is a maintenance release to fix a critical bug and three security issues; we urge all users to upgrade.

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), 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 0.8.4 your blockchain files will be re-indexed, which will take anywhere from 30 minutes to several hours, depending on the speed of your machine.

0.8.4 Release notes

Security issues

An attacker could send a series of messages that resulted in an integer division-by-zero error in the Bloom Filter handling code, causing the Bitcoin-Qt or bitcoind process to crash. Bloom filters were introduced with version 0.8, so versions 0.8.0 through 0.8.3 are vulnerable to this critical denial-of-service attack.

A constant-time algorithm is now used to check RPC password guess attempts; fixes (CVE-2013-4165)

Implement a better fix for the fill-memory-with-orphan-transactions attack that was fixed in 0.8.3. See for a description of the weaknesses of the previous fix. (CVE-2013-4627)

Bugs fixed

Fix multi-block reorg transaction resurrection.

Fix non-standard disconnected transactions causing mempool orphans. This bug could cause nodes running with the -debug flag to crash.

OSX: use 'FD_FULLSYNC' with LevelDB, which will (hopefully!) prevent the database corruption issues many people have experienced on OSX.

Linux: clicking on bitcoin: links was broken if you were using a Gnome-based desktop.

Fix a hang-at-shutdown bug that only affects users that compile their own version of Bitcoin against Boost versions 1.50-1.52.

Other changes

Checkpoint at block 250,000 to speed up initial block downloads and make the progress indicator when downloading more accurate.

Thanks to everybody who contributed to the 0.8.4 releases!

  • Pieter Wuille
  • Warren Togami
  • Patrick Strateman
  • pakt
  • Gregory Maxwell
  • Sergio Demian Lerner
  • grayleonard
  • Cory Fields
  • Matt Corallo
  • Gavin Andresen