SFML has been using SMF (Simple Machines Forum) for many years. While it's been a good enough experience, there are three problems that would encourage us to move away from SMF:
The software foundation is decades old and there isn't a goal insight to completely modernize to a "safer" architecture
The plugin system is beyond horrible, patching the actual core files with diff-patches, which is especially "fun" if you have multiple plugins patch the same file
The theme is not mobile friendly, even with some adjustments it will probably always have certain limitations, as mobile usage was non-existent when SMF was originally created
Software Selection
Some of the Requirements:
Easily self-hostable
Non-commercial, or no recurring cost
Preferable "boring tech", best matching our current stack (PHP, MariaDB, Nginx)
No massive scaling required (max concurrent users ~300)
SFML has been using SMF (Simple Machines Forum) for many years. While it's been a good enough experience, there are three problems that would encourage us to move away from SMF:
Software Selection
Some of the Requirements:
Migration Path