What works with all browsers that I've tested (IE, Edge, Opera, Konqueror, and Firefox) is to load the
favicon.ico in a separate tab - that forces the updating of the cache.
With Firefox right-click on the DokuWiki page and choose
View Page Info from the drop-down menu, then click on the
Media tab. Scroll down the list of media until you see the link ending in favicon.ico, type is Icon - then copy the URL and post it into a new tab. After which if you reload the original page you'll see the updated favicon.ico
Or - either read the source code for the page, or use some Linux shell scripting (where
$URL is the path to your DokuWiki):-
curl $URL | grep favicon
[/color]
If you still don't see the updated
favicon.ico it is likely you have more than one
favicon.ico (e.g. in the root of your web directory) - in which case you need to examine
the order in which the browser looks in places for the
favicon.ico.