WP Browser Compatibility Checker adds minimum browser comptibility settings to allow the administrator to define which browsers and versions will provide the optimum experience.
When someone browsing the website is not using the minimum requrired browser version they will be notified that their experience on the website may not be as good as it could be.
If the person browsing the website closes the notice they will not see it again for 3 days.
Extract the zip file and just drop the contents in the wp-content/plugins/ directory of your WordPress installation and then activate the Plugin from Plugins page.
Go to \”Browser Warning\” under Appearance and set the minimum browser compatibility for the website.