April 2026 monthly summary for renovate-bot/apache-_-polaris focused on delivering a robust upgrade of the Polaris testing framework to JUnit 6, improving reliability and future-proofing the codebase. Key features delivered: JUnit 6 Compatibility Upgrade for Polaris Testing Framework. This involved refactoring deprecated API calls and aligning the test infrastructure with JUnit 6, ensuring smoother future migrations and reduced risk of test regressions. Commit 9618be68fb25bc6e4c924381d3ba9006a2e292ce accompanied the change and included a note in CHANGELOG.md about enforcing JUnit 6 usage downstream. Major bugs fixed: Addressed deprecations and upgrade blockers by migrating from getOrComputeIfAbsent() to computeIfAbsent() in org.junit.jupiter.api.extension usage, removing legacy API friction and stabilizing the test suite under JUnit 6. This reduces maintenance overhead and mitigates potential test failures during downstream upgrades. Overall impact and accomplishments: Strengthened testing reliability, reduced downstream upgrade risk, and improved maintainability of the Polaris codebase. The upgrade enables faster release cycles with a stable CI pipeline and ensures downstream consumers can migrate to JUnit 6 with minimal friction. Technologies/skills demonstrated: Java, JUnit 6, refactoring of deprecated APIs, API migration, test infrastructure modernization, changelog documentation, and downstream impact awareness.