MapServer Migration Guide
The current version of the MapServer Migration Guide is available online at https://mapserver.org/MIGRATION_GUIDE.html.
For developers:
The main copy of the MIGRATION_GUIDE is now located in the root of the /MapServer/MapServer-documentation source tree ( https://github.com/MapServer/MapServer-documentation ). Developers are welcome and encouraged to edit/update the guide in the documentation tree directly.