Armin Sabouri focused on enhancing transaction reliability in the cake_wallet repository by addressing a critical Replace-By-Fee (RBF) compatibility issue. He updated the RBF sequence number handling to 0xFFFFFFFD using Dart, aligning the wallet’s behavior with industry standards and reducing the risk of unintended bugs in collaborative blockchain workflows such as payjoin. This change improved interoperability and minimized fingerprinting risks, supporting safer multi-party transactions. Armin’s work demonstrated a deep understanding of blockchain development and wallet engineering, as he carefully balanced protocol compliance with practical security considerations. His contributions reflect thoughtful, targeted problem-solving within the Dart programming ecosystem.