Dana Ross

This plugin displays a message at the top of the screen for visitors running outdated versions of the most popular browsers:
<ul>
<li>Internet Explorer 6 SP2 or less</li>
<li>FireFox 2 or less</li>
<li>Safari 2 or less</li>
</ul>
It is designed to be unobtrusive. The message disappears after a few seconds, and it only displays the first time the visitor comes to your WordPress blog/site.
The warning reads: It appears that you are using an outdated version of your browser. Please upgrade your browser for better sercurity and an improved experience.
The message also includes a link where the newest version of the browser can be downloaded.

Dave’s Outdated Browser Warning

mendibass

Paint the top address bar of a selected page, you can choose different color for every page.
<ul>
<li>Not supported yet in desktop browsers, 
Works on Chrome and Samsung Internet mobile browsers</li>
</ul>
<h3>Donations</h3>

Browser Address Bar Color

Perfect

Customize your mobile browsing experience by setting theme colors for the address bar of your pages on your WordPress site

Dave’s Outdated Browser Warning vs Browser Address Bar Color