Andrey Avdeev enhanced the diadocsdk-csharp and diadocsdk-java repositories by expanding the PowerOfAttorney data model to support new issuer types and timezone-aware fields, improving cross-language consistency and integration safety for client applications. He implemented these features using Java, C#, and Protocol Buffers, focusing on robust API development and data modeling. Andrey synchronized changes across both SDKs, ensuring interoperability and reducing integration risks. In addition, he managed build processes by updating versioning in diadocsdk-java, supporting reproducible builds and reliable dependency resolution. His work demonstrated depth in backend development, code generation, and careful attention to release management and cross-platform alignment.