Issues and versions management has finally moved to Github.
A git mirror was already available for a few months and keeping both locations up-to-date required a lot of work.
Additionally, I realized using both systems than github's issues tracker was more simple to use than Redmine's one. It provides less functionalities but they are enough for Modoboa's needs.
Existing versions and issues have been migrated using a home-brewed script but original identifiers have been lost due to technical reasons. Anyway, history has been preserved, it's the most important!
The Redmine instance will remain online for a few month but accounts and issues creation are already disabled.