Bitcoin version 0.3.21 released
27 April 2011

Changes and new features from the 0.3.20 release include:

Universal Plug and Play support. Enable automatic opening of a port for incoming connections by running bitcoin or bitcoind with the
-upnp=1 command line switch or using the Options dialog box.
Support for full-precision bitcoin amounts. You can now send, and bitcoin will display, bitcoin amounts smaller than 0.01. However, sending fewer than 0.01 bitcoins still requires a 0.01 bitcoin fee (so you can send 1.0001 bitcoins without a fee, but you will be asked to pay a fee if you try to send 0.0001).
A new method of finding bitcoin nodes to connect with, via DNS A records. Use the -dnsseed option to enable.

For developers, changes to bitcoin’s remote-procedure-call API:

New rpc command “sendmany” to send bitcoins to more than one address in a single transaction.
Several bug fixes, including a serious intermittent bug that would sometimes cause bitcoind to stop accepting rpc requests.
-logtimestamps option, to add a timestamp to each line in debug.log.
Immature blocks (newly generated, under 120 confirmations) are now shown in listtransactions.

Bitcoin version 0.3.21 released27 April 2011