During January 2026, Kosmx developed ProtoBuf support for Kotlin unsigned types, specifically UByteArray and UInt, within the kotlinx.serialization repository. This work involved implementing encoding and decoding logic to handle these types correctly, addressing issues with ProtoBuf packing to ensure data integrity. Kosmx expanded test coverage to include edge cases and regression scenarios, enhancing reliability for projects relying on ProtoBuf serialization. The technical approach centered on Kotlin and serialization techniques, with a strong emphasis on testing to validate the new functionality. The depth of the work is reflected in the comprehensive handling of unsigned types and the focus on robust test coverage.