jbalde

UserAgent Theme Switcher is a simple plugin which lets you change the theme to be displayed according to the detected browser.
Checks from a predefined list useragent so that the user can at will change the theme shown for that browser. 
A user can configure a special theme for example for mobile phones that is lighter and this adapted to these devices
Ideal for displaying themes ready to opera mobile, internet explorer mobile, iphone, android, etc.
Now the cache is not supported but will work so that if it is supported in the future

UserAgent Theme Switcher

UserAgent Theme Switcher is a simple plugin which lets you change the theme to be displayed according to the detected browser

Deblyn Prado

So, you’re tired of people visiting your modern website with an outdated browser and not doing anything about it. Maybe they aren’t “power” users, maybe it’s your auntie running a last century browser trying to see awesome CSS3 animations and transforms. Let the user know that’s an outdated browser, and advise them on a better one.
With this solution you can check if the user’s browser can handle your website. If not, it will show a cool looking notice advising the user to update the browser. It\’ll be up to him/her to decide if he upgrades or not. Don’t force the user!
This plugin is a version of <a href="http://outdatedbrowser.com/" rel="nofollow ugc">Outdated Browser Projetct</a> created by <a href="https://github.com/burocratik" rel="nofollow ugc">Bürocratik</a>

WP Outdated Browser

Show a message if the user using a outdated browser.

UserAgent Theme Switcher vs WP Outdated Browser