Our wiki is publicly available and editable. However, several times a year, our top contributors go to remote areas without reliable internet access for long periods of time. This is also when they have a lot of free time to edit the wiki if they could access it.
We're considering setting up a raspberry pi as an off-grid LAMP server with MediaWiki. Copying over the database and upload directory with the most up to date version of the site, and letting them take it with them. Once they get back we would merge the forked wikis.
But that's where the problem is. What's the best way to merge the two together? Theoretically some pages would be edited by one group and unedited by the other. But some pages could have edits by both groups, some of which don't conflict while others do.