There is no COMPELLING reason to update CSS Hero on older legacy sites. No security problem arises from keeping v3.
Upgrading makes sense only if you plan tinkering a lot with CSS Hero, and thus you want to run the latest version.
Here is the recommended path:
Let’s say you have a site running CSS Hero v3.something.
– Disable the CSS Hero v3 plugin – and delete it.
– Download latest v4 from your dashboard), install and activate the plugin.
– Launch the CSS Hero editor (it will be v4 of course).
– You will be asked if you want to import your v3 data. Go for it!
– Hit the Save and publish button.
Done. It should work in most cases, especially if you didn’t do lots of edits.
Reverting in case something screws up
Remember you can “go back” and easily revert to CSS Hero 3.x
Consider that v3 and v4 save data onto separate data tables.
In case you want to go back to v3:
Just deactivate and delete the new plugin and install the old one (you can find v3 in the Utilities & Legacy Downloads section in your dashboard).
all CSS will go back to what used to be on v3.x – and your site will look as it used to be.