Worked on the PriorLabs/TabPFN repository to address a regression affecting compatibility with older PyTorch versions. Focused on restoring the original GQA API detection logic, the developer identified and fixed an issue where detection was bypassed for PyTorch versions prior to 2.5, which had led to runtime errors for some users. The solution involved careful debugging and alignment with the original implementation to ensure consistent behavior across different PyTorch releases. Utilizing Python and PyTorch, the work enhanced the reliability of the API detection mechanism, reduced user-reported compatibility issues, and demonstrated a methodical approach to regression resolution and cross-version support.