The Rust-Lightning v0.2.1 release includes several API updates and bug fixes. Notably, the `AttributionData` struct is now public, resolving issues with message construction. The async background processor has been improved to exit promptly when required. Bug fixes address issues such as the `ElectrumSyncClient` handling unconfirmed transactions more reliably, and the `ChannelManager::splice_channel` now correctly fails if the peer does not support splicing. Additionally, logging for outbound payments has been enhanced to include the `payment_hash` field.