Bitcoin v0.3.12 was released on SourceForge on September 7, 2010. This release continued the rapid series of updates that followed the critical v0.3 line, addressing various bugs and improving network stability during a period of growing adoption.
Notable changes in v0.3.12:
- Key pool feature — pre-generates 100 keys in advance so that wallet backups remain valid for future transactions, addressing a significant usability concern where old backups could lose access to newly generated addresses
- Various bug fixes and performance improvements
- Network protocol improvements
The key pool feature was a significant quality-of-life improvement. Prior to this change, each time Bitcoin generated a new address (which happened automatically for change outputs), a fresh backup would be needed to include the new key. The key pool mitigated this by pre-generating keys, giving users a buffer of addresses that would already be included in existing backups.
By this point in September 2010, Satoshi was still actively leading development but was increasingly sharing responsibility with other contributors including Gavin Andresen, who had been gaining a more prominent role in the project.