Practical reference material for maintaining and upgrading legacy Grails applications in institutional and enterprise environments.
This repo focuses on real upgrade work: planning, risk reduction, execution, and post-upgrade validation.
- Existing Grails applications (primarily 2.x → 6.x)
- Production-facing systems
- Long-lived institutional codebases
- Emphasis on safety, repeatability, and documentation
These are production-facing artifacts used during real Grails upgrades. They are intentionally provided as styled HTML plus print-friendly versions.
- Questionnaire (screen)
playbooks/pre-upgrade-questionnaire.html - Questionnaire (print)
playbooks/pre-upgrade-questionnaire-print.html
- Upgrade Playbook (screen)
playbooks/upgrade-playbook.html - Upgrade Playbook (print)
playbooks/upgrade-playbook-print.html
Print versions are designed for desk reference during active upgrade work.
- Grails 6 upgrade strategy
- Java 17 alignment
- Gradle wrapper upgrades
- Plugin compatibility audits
- Configuration migration (
application.yml) - GORM and Groovy API changes
- Post-upgrade validation and rollout
- Boring is good — predictable upgrades beat clever ones
- Capture state before touching code
- Upgrade in small, verifiable steps
- If it isn’t written down, it doesn’t exist
Active — maintained alongside ongoing Grails upgrade work.
Guidance assumes existing production systems and may not apply to new applications.