If, like me, you use a theme for your Wordpress installation, and if, like me, you were too lazy to create a child theme when you edited the theme, you might find yourself being reminded from time to time about theme updates when you don't want to, or can't, update your theme.
To get rid of the reminders without having to update your theme is easier than you might think - Wordpress simply checks your current version against the latest available version, so all you have to do is fool it into thinking that your current version is the latest version.
Suppress Theme Update Reminders
Simply find the style.css for your theme - this will generally be at wp-content/themes/yourtheme/style.css - and download and open it, or edit it through Wordpress's built-in editor. In the top section there'll be a set of comments which look something like this :
Theme Name: Esquire
Theme URI: http://theme.wordpress.com/themes/esquire
Author: Matthew Buchanan
Author URI: http://matthewbuchanan.name/
Description: An elegant and bold theme featuring multiple, visually distinct, Post Formats. Designed by Matthew Buchanan and inspired by the art direction of Esquire magazine.
License: GNU General Public License
License URI: license.txt
Tags: light, red, white, yellow, two-columns, fixed-width, custom-menu, featured-images, post-formats, sticky-post, translation-ready
(the above is from the comments for my theme).
To suppress the reminders, simply change the Version number to whatever the latest version is (Wordpress will be telling you this in the update section of the admin panel) and save your changes - if you're changing over FTP, upload the new version in place of the old. And voila - reminders will disappear (until the next time). I haven't tested to see if you can suppress them permanently by changing version number to 100, but it's probably worth a shot!