The bootstrap css version is rather old

[sebbASF]

The site currently uses 3.4.0, which is not even the latest in its series.
The current version is 5.3.2

[bdelacretaz]

Is that a problem that should be fixed right now?

I'm afraid upgrading the CSS might cause subtle issues that are hard to detect given the large number of pages.

Maybe just mentioning this in the README, so that people are aware when the time comes to upgrade the presentation, would be sufficient?