he Liferay CMS needs to be upgraded to version 7.1, and I am currently preparing for this.
Unfortunately, things are not going very smoothly, and one of the problems we have is that the current Wiki Format used in our Wiki, called "MediaWiki", has been dropped from the available formats.
Therefore it is imperative that the old wiki pages and any new wiki pages you might be making will use the Wiki Format "Creole". You can change this per wiki page under the header "Configuration".
Rest assured that nothing of the Wiki will be lost during the upgrade (I'm making sure), but for pages in the old format, it will revert to "Plain text", which is quite ugly and you'll receive the message that the format is no longer supported.
Also unfortunately, it seems Creole does not support quite the range of possibilities that MediaWiki did.