To get bitcoinj 0.7, check out our source from git and then run git reset --hard a9bd8631b904. This will place you on the 0.7 release in a secure manner. This paragraph was written on Tuesday 19th February 2013 and is signed with the following key, which will be used in all release announcements in future: 16vSNFP5Acsa6RBbjEA7QYCCRDRGXRFH4m.

Signature for the last paragraph: IMvY1FsQobjU2t83ztQL3CTA+V+7WWKBFwMC+UWKCOMyTKA+73iSsFnCHdbFjAOEFMQH/NvJMTgGeVCSV/F9hfs=

If you want to, you can check that the original announcement mail sent to bitcoinj@googlegroups.com is correctly signed with the google.com DKIM key, to establish a full chain of trust.

• Thanks to Matt Corallo, we now support a fully verifying mode in addition to simplified verification. This is a tremendous amount of work that wouldn't have happened without Matt! Right now, we strongly discourage anyone from using it for mining (which is not supported out of the box anyway). Use it in a production environment only if you know what you're doing and are willing to risk losing money. If you do use it, let us know so we can contact you when problems are discovered. Read the documentation carefully before you begin.
• Also thanks to Matt, Bloom filtering is now implemented and activated by default. When bitcoinj connects to a peer that supports Bloom filtering, only transactions relevant to the wallet will be downloaded which makes bandwidth usage scale with the size of your wallet, not global system activity. A configurable false positive ratio allows you to trade off bandwidth vs privacy. App developers don't need to do anything to take advantage of this, it is enabled automatically.
• PeerGroup now pings its peers and calculates moving averages of the ping times. Ping time, versions and block heights are taken into account when selecting the peer to download the chain from.
• You can now customize which outputs the wallet uses to create spends. The new default coin selector object allows you to spend unconfirmed change as long as it's been seen propagating across the network, addressing a common end-user pain point in wallet apps.
• Optimized networking code for faster startup.
• A new PeerMonitor example app shows how to put properties of connected peers into a GUI.
• The Wallet is now decoupled from the BlockChain using the new BlockChainListener interface. This will simplify the development of some apps that want to process transactions but not maintain an actual wallet.
• The dependencies of broadcast transactions are now downloaded and risk analyzed. At the moment they are only being checked for having a timelock. In future we may also analyze tree depth. The goal is to make certain kinds of protocol abuse harder. Wallets will reject timelocked transactions by default, this can be overridden via a property.
• You can now create timelocked transactions with WalletTool? if you want to.
• Compressed public keys are now used by default.
• Support testnet3
• Support bitcoin-qt compatible message signing and verification.
• ECDSA key recovery is now implemented and allows you to obtain the public key from an extended signature. If the signature is not extended then there are multiple key possibilities returned.
• Many bugfixes and minor improvements

API changes:

• ECKey.sign() now takes a Sha256Hash as an argument and returns an ECDSASignature object in response. To get DER encoded signatures, use the encodeToDER() method of ECDSASignature.
• ECKey.publicKeyFromPrivate now takes an additional compressed parameter.
• PeerGroup.start()/PeerGroup.shutDown() now run asynchronously and return futures you can use to wait for them. You cannot restart aPeerGroup once it has been shut down any more.