[xet7]

Here is answer for WeKan https://wekan.github.io

Order is stored to sort field as number. When changing order with JQuery Draggable/Droppable/Sortable, it saves new order to browserside MiniMongo, that is made with Javascript, and then to serverside MongoDB. It is possible use mouse or touchscreen to drag drop reorder board icons at All Boards page, swimlanes, lists, cards and checklists. There are also roles at right sidebar avatar icons popup settings, so BoardAdmin can drag drop everything, and there are some limits for other roles, like Normal, CommentOnly etc https://news.ycombinator.com/item?id=44165257

For realtime updates, Meteor web framework reads realtime changes from MongoDB OpLog (operations log), and with Publish/Subscribe at realtime updates all changes immediately for all users, like what card moved, etc.

There is in progress of adding support for other databases, like SQLite etc.

[GlacierFox]

Thank your for this info!