In my case, Redmine 3.1.0 and MySQL are used as the database server. I think you will get the main idea in the case of a different Confucius.
DELETE FROM `enabled_modules` WHERE `name` = 'module_name_here'; INSERT INTO `enabled_modules` (`project_id`, `name`) SELECT `id`, 'module_name_here' FROM `projects`
You can activate a module for one project to find out its name from enabled_modules. Or you can find it in the plugin sources, it should look like "project_module: module_name_here"
Please do not do this if you do not quite understand what this answer is about!
PS: Yes, I know - this is a dirty solution, but it is fast and easy enough for work that is required once a year or less.
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