We're releasing 0.6.3 to fix two important issues (a serious potential denial-of-service attack, and to improve new-block propagation times for blocks containing lots of transactions).
If you can, please help do some sanity testing-- shutdown bitcoin, then download, install, and run 0.6.3 and let us know "works nicely for me running on 64-bit Ubuntu 10.04" by posting a quick reply to this thread.
Bitcoin version 0.6.3rc1 is now available for download at: http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.6.3/test/
This is a bug-fix release, with no new features.
Fixed a serious denial-of-service attack that could cause the
bitcoin process to become unresponsive. Thanks to Sergio Lerner
for finding and responsibly reporting the problem. (CVE-2012-3789)
Optimized the process of checking transaction signatures, to
speed up processing of new block messages and make propagating
blocks across the network faster.
Fixed an obscure bug that could cause the bitcoin process to get
stuck on an invalid block-chain, if the invalid chain was
hundreds of blocks long.
Bitcoin-Qt no longer automatically selects the first address
in the address book (Issue #1384).
Fixed minimize-to-dock behavior of Bitcon-Qt on the Mac.
Added a block checkpoint at block 185,333 to speed up initial
Thanks to everybody who contributed to this release:
Christian von Roques
R E Broadley
Wladimir J. van der Laan