September 2025 focused on delivering feature-rich Lightning invoice capabilities, configurable Spark integration controls, and enhanced wallet seed management, while stabilizing the codebase for long-term reliability. Key outcomes include improved privacy and flexibility in payment flows, support for mnemonic seeds with optional passphrases, and build/stability improvements that reduce production risk and maintenance effort.

In 2025-08 Breez Spark SDK delivered a key performance feature by refactoring DefaultSigner to use a KeyPair for identity_key, reducing repeated derivation of the identity public key and enabling faster signing and verification. This supports higher throughput and lower CPU usage in identity operations, aligning with the project’s performance goals. The change is captured by a single commit implementing KeyPair-based identity_key (8a03a7712db18bd9684e94292cf989b3aa215174).

July 2025 monthly summary for breez/spark-sdk focused on API ergonomics and public surface enhancements to simplify downstream usage and accelerate wallet integration workflows.

Month: 2025-05. Documentation-focused improvement for fundrawtransaction RPC fee calculation in bitcoin/bitcoin; clarified that the fee rate applies to the entire transaction package, especially when unconfirmed inputs are present. This reduces ambiguity for developers and aligns expectations with package-level fee computation.