Of course you keep up to date backups so it goes without saying. But just in case you lose today’s data you should first backup your database and your web-root to. I simple downloaded the whole of my Silverstripe web-root to my local machine (using FTP with the Krusader application). Then I logged into my hosts admin pages and used phpMyAdmin to run a dump of my database (“Export” it’s called).
As I’m a belt-and-braces kinda guy I also used my hosts backup system (via Plesk Control Panel) to take a full domain backup whilst I was in a backing up sort of mood.
Next I purged the application cache deleting all the files in ./webroot/silverstripe-cache/.
Then following the advice on Silverstripe.org (along with tips from their forum and some other info on version 2.4.0) I removed the following folders:
* ./jsparty (this was removed in 2.4.0 in preference to putting the relevant js in the cms and sapphire folders)