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Bitcoin-Qt 0.5.3

Bitcoin version 0.5.3 is now available for download at:

This is a bugfix-only release based on 0.5.1. It also includes a few protocol updates.

Please report bugs using the issue tracker at github:

Stable source code is hosted at Gitorious:


  • BIP 30: Introduce a new network rule: "a block is not valid if it contains a transaction whose hash already exists in the block chain, unless all that transaction's outputs were already spent before said block" beginning on March 15, 2012, 00:00 UTC.
  • On testnet, allow mining of min-difficulty blocks if 20 minutes have gone by without mining a regular-difficulty block. This is to make testing Bitcoin easier, and will not affect normal mode.


  • Limit the number of orphan transactions stored in memory, to prevent a potential denial-of-service attack by flooding orphan transactions. Also never store invalid transactions at all.
  • Fix possible buffer overflow on systems with very long application data paths. This is not exploitable.
  • Resolved multiple bugs preventing long-term unlocking of encrypted wallets (issue #922).
  • Only send local IP in "version" messages if it is globally routable (ie, not private), and try to get such an IP from UPnP if applicable.
  • Reannounce UPnP port forwards every 20 minutes, to workaround routers expiring old entries, and allow the -upnp option to override any stored setting.
  • Skip splash screen when -min is used, and fix Minimize to Tray function.
  • Do not blank "label" in Bitcoin-Qt "Send" tab, if the user has already entered something.
  • Correct various labels and messages.
  • Various memory leaks and potential null pointer deferences have been fixed.
  • Handle invalid Bitcoin URIs using "bitcoin://" instead of "bitcoin:".
  • Several shutdown issues have been fixed.
  • Revert to "global progress indication", as starting from zero every time was considered too confusing for many users.
  • Check that keys stored in the wallet are valid at startup, and if not, report corruption.
  • Enable accessible widgets on Windows, so that people with screen readers such as NVDA can make sense of it.
  • Various build fixes.
  • If no password is specified to bitcoind, recommend a secure password.
  • Automatically focus and scroll to new "Send coins" entries in Bitcoin-Qt.
  • Show a message box for --help on Windows, for Bitcoin-Qt.
  • Add missing "About Qt" menu option to show built-in Qt About dialog.
  • Don't show "-daemon" as an option for Bitcoin-Qt, since it isn't available.
  • Update hard-coded fallback seed nodes, choosing recent ones with long uptime and versions at least 0.4.0.
  • Add checkpoint at block 168,000.