Version 7.8.0 Released

This release has many improvements around bootstrapping and network usage. It's recommended that everyone upgrade.

Bootstrapping:

• Downloaded blocks were being inappropriately deleted causing them to be downloaded again
• A database lock was being held open too long preventing bootstrap forks from being evicted.

Networking:

• Added UPnP to automatically map ports with routers
• Rebroadcasting blocks to a smaller set of nodes instead of global.