Is a special upgrade procedure required to migrate from 1.27 LTS to 1.31 LTS?
Topic on Talk:MediaWiki 1.31/Flow
The biggest change will likely be any extensions that might stop being compatible with the new version. In particular, I don't think Semantic Mediawiki supports 1.31 yet (as of May 2018).
> In particular, I don't think Semantic Mediawiki supports 1.31 yet (as of May 2018).
This is officially try but I do not think that your wiki will go berserk. The "official" sandbox wiki is now using MW 1.31