During April 2025, 21m4tw focused on backend development within the lightningd/plugins repository, addressing a nuanced bug in the rebalancing logic. They implemented a Python-based fix to ensure that the find_worst_channel function correctly identifies the middle channel in short routes of length three, rather than returning None. This targeted change improved the reliability of liquidity management by preventing failures in edge-case routing scenarios. By confining the update to the plugin layer, 21m4tw maintained interface stability while enhancing route robustness. The work demonstrated careful attention to risk mitigation and a deep understanding of Python and backend systems, though the scope was narrowly focused.