Worked on enhancing backward compatibility testing for Cassandra SSTable formats in the apache/cassandra repository, focusing on serialization integrity between versions 3.0.25 and 3.11.11. Developed new test data for legacy SSTable formats and implemented methods to verify the behavior of frozen tuples and their dropping across these versions. This work expanded the coverage of backward compatibility tests, ensuring that data structures and file I/O operations remained consistent during version upgrades. Leveraged Java and testing frameworks to automate validation, contributing to more robust cross-version support. The approach emphasized thoroughness in testing, addressing potential issues in data migration and serialization workflows.