This feature prevents php code inside smarty, for security reasons.
because of this new feature, aulawiki.1.7.2 cannot work in tw 3.x, unless you set it off.
I had to replace mod-workspace_calendar with mod-calendar_new
Please take alook at the smarty template of mod-workspace_calendar:
mod-workspaces_calendar template as before latest update
It's a lot of php meshed inside smarty! Taking away all php code means rewriting the calling module completely! When there exist a nice, maintained and up to date one named mod-calendar_new.
This is the reason why I switched on using the cherry mod-calendar_new module.