It’s unlikely that your website still has any content on it which is built using a web technology called ‘Flash’. But if you do, make it a priority to remove it. That’s because Google’s widely-used Chrome browser is about to stop supporting it automatically. In this, it joins most mobile devices. Also check that you don’t have any adverts running online which use Flash, as that’s been a common application of the technology in the past.
Chrome will run Flash, but it’ll need to be enabled by the user, which is not ideal, especially if your content is marketing material.