Nils Uhrberg modernized the Feast integration within the zenml-io/zenml repository by refactoring the API to use FeatureService instances directly, enabling more flexible and scalable feature retrieval. He updated core methods to accept either feature names or FeatureService objects, improving usability and compatibility while raising the minimum supported Feast Python API version to 0.12.0. In a separate effort, Nils enhanced the reliability of time-related features by replacing deprecated datetime handling with UTC-aware datetimes throughout the codebase. His work demonstrated strong skills in Python, API integration, and refactoring, addressing maintainability and robustness in both feature development and bug resolution.