
Bitcoin is an experimental new digital currency that enables instant payments to anyone, anywhere in the world. Bitcoin uses peer-to-peer technology to operate with no central authority: managing transactions and issuing money are carried out collectively by the network. Bitcoin is also the name of the open source software which enables the use of this currency.
v0.4.0 [Sep 24, 2011]
The main feature in this release is wallet private key encryption; you can set a passphrase that must be entered before sending coins. See below for more information; if you decide to encrypt your wallet, WRITE DOWN YOUR PASSPHRASE AND PUT IT IN A SECURE LOCATION. If you forget or lose your wallet passphrase, you lose your bitcoins. Previous versions of bitcoin are unable to read encrypted wallets, and will crash on startup if the wallet is encrypted.
Also note: bitcoin version 0.4 uses a newer version of Berkeley DB (bdb version 4.8) than previous versions (bdb 4.7). If you upgrade to version 0.4 and then revert back to an earlier version of bitcoin the it may be unable to start because bdb 4.7 cannot read bdb 4.8 “log” files.