When I was browsing the gallery tag page of Wikipedia I just noticed there is a slideshow there for the mediawiki gallery, which I found strange because I thought slideshows aren't natively supported in the MediaWiki galleries. I also tried out it's code here on this wiki on the Sandbox page to test if it's working here as well, and it's working fine, but when I tried it on my own wiki it doesn't seem to work. What should I do to enable this functionality on my wiki? My wiki's version is 1.27(LTS).
Example of the slideshow code I found:
<gallery mode="slideshow"> File:Detroit Publishing Co. - A Yeoman of the Guard (N.B. actually a Yeoman Warder), full restoration.jpg|A Yeoman Warder, from a Victorian-era [[photochrom]] File:Official_program_-_Woman_suffrage_procession_March_3,_1913_-_crop.jpg|The Official program of the 1913 Woman Suffrage Procession held in Washington, D.C. File:Thurston, the famous magician - East Indian Rope Trick.jpg|[[Howard Thurston]] performing the [[Indian rope trick]] File:Joseph Ferdinand Keppler - The Pirate Publisher - Puck Magazine - Restoration by Adam Cuerden.jpg|"The Pirate Publisher", a satire of copyright infringement from the magazine [[Puck (magazine)|Puck]]. </gallery>