---
title: Bitcoin-Qt version 0.8.6 released
---
Bitcoin-Qt version 0.8.6 is now available from:
  <http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.8.6/>

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

Please report bugs using the issue tracker at github:
  <https://github.com/bitcoin/bitcoin/issues>


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

0.8.6 Release notes
===================

- Default block size increase for miners.
  (see <https://gist.github.com/gavinandresen/7670433#086-accept-into-block>)

- Remove the all-outputs-must-be-greater-than-CENT-to-qualify-as-free rule for relaying
  (see <https://gist.github.com/gavinandresen/7670433#086-relaying>)

- Lower maximum size for free transaction creation
  (see <https://gist.github.com/gavinandresen/7670433#086-wallet>)

- OSX block chain database corruption fixes
  - Update leveldb to 1.13
  - Use fcntl with `F_FULLSYNC` instead of fsync on OSX
  - Use native Darwin memory barriers
  - Replace use of mmap in leveldb for improved reliability (only on OSX)

- Fix nodes forwarding transactions with empty vins and getting banned

- Network code performance and robustness improvements

- Additional debug.log logging for diagnosis of network problems, log timestamps by default

- Fix Bitcoin-Qt startup crash when clicking dock icon on OSX 

- Fix memory leaks in CKey::SetCompactSignature() and Key::SignCompact()

- Fix rare GUI crash on send

- Various small GUI, documentation and build fixes

Warning
-------

- There have been frequent reports of users running out of virtual memory on 32-bit systems
  during the initial sync.
  Hence it is recommended to use a 64-bit executable if possible.
  A 64-bit executable for Windows is planned for 0.9.

