MacSteini

Many users still browse with outdated browsers, often unaware of the risks. Upgrading ensures better security and reliability. This plugin displays a subtle notification prompting visitors to update their browser. Activate the plugin, and it works seamlessly.
WP BrowserUpdate is based on the browser-update.org detection logic. The plugin now runs independently from browser-update.org at display time: the visitor-facing notification is served from the plugin’s own bundled runtime files, so sites do not need to load scripts, styles, or default notification links from browser-update.org. browser-update.org remains the credited upstream source for the bundled detection logic, and future runtime refreshes are tracked with source URLs and hashes in the plugin assets.
Visit <a href="https://browserupdate.org/" rel="nofollow ugc">browserupdate.org</a> for more details about the upstream project.
Want to help translate this plugin? Visit the <a href="https://translate.wordpress.org/projects/wp-plugins/wp-browser-update" rel="nofollow ugc">WordPress Translation Project</a>.
<h3>How it works</h3>
WP BrowserUpdate bundles browser-update.org detection logic for WordPress. After activation, the plugin loads the local notification runtime from the plugin directory and passes your configured browser-version thresholds to those scripts. The notification is shown only when the bundled detection logic matches a browser to your settings.
The settings page is available under Settings > WP BrowserUpdate. You can define browser versions for every browser key supported by the bundled browser-update.org runtime, choose where the message appears and which element should contain it, enable testing mode, decide whether mobile or unsupported browsers should be notified, customize links, language and message text, and add trusted custom CSS for the notification.
Browser version fields accept major versions such as <code>115</code> and positive dotted versions such as <code>137.0.3912.63</code>. Dotted versions are passed exactly to the bundled runtime instead of being reduced to their major version; exact comparison depends on the bundled browser-update.org logic and the browser key used by that runtime. A value of <code>0</code> uses the default bundled outdated-browser detection. Negative whole numbers are passed to the bundled runtime as relative offsets from the current bundled upstream version.
Microsoft Edge and Microsoft Internet Explorer have separate settings now.
This local runtime design avoids frontend blocking of external script URLs on sites with strict Content Security Policies or tracker blocking. WP BrowserUpdate ships only the local runtime and CSP adapter files needed by the plugin.
<h3>Important Notice</h3>
Breaking Changes in Version 6.0 
– Requires WordPress 6.0 or newer. 
– Introduces a new structured settings model to support the browser-update.org customization surface used by WP BrowserUpdate. 
– Moves the visitor-facing browser-update.org runtime into the plugin package so strict Content Security Policies and tracker blockers no longer need to allow scripts from <code>browser-update.org</code>. 
– Existing WP BrowserUpdate settings from version 5.x are migrated automatically.
Breaking Changes in Version 5.0 
– Requires PHP 7.4 or newer. 
– Ensure your hosting is updated to PHP 7.4 before upgrading to version 5.0 or newer. 
– Servers running older PHP versions are no longer supported. 
 – If your server is running an earlier PHP version, please download <a href="https://downloads.wordpress.org/plugin/wp-browser-update.4.8.1.zip" title="Download WP BrowserUpdate from WordPress.org" rel="nofollow ugc">version 4.8.1</a>.

WP BrowserUpdate

Used for a client who had this exact request. Worked well.

Works as expected

This plugin notifies website visitors to update their outdated browser in a non-intrusive way.

Mario Peshev

DevriX

DX Out of Date allows you to display a notification box on your posts 
when a given amount of time has passed. Quite handy when writing tutorials 
or any content that might get outdated due to external factors – now you 
could automatically notify your readers after a given period.
You can configure the expiration time of your posts in the admin panel. Valid time units are days, months and years.
Currently the plugin options are:
<ul>
<li>Period – “amount” of “duration” units (1 to 40)</li>
<li>Duration frame (days, months, years)</li>
<li>Message – the message format for the notification box</li>
<li>Enable by default – a checkbox for enabling the message on all posts by default</li>
<li>Enable post status in Dashboard – a checkbox for adding an extra column in the Dashboard for the outdated status of posts</li>
<li>Post types to affect – allows you to choose which post types for display the message for</li>
<li>Position of the message – choose whether the message should be displayed at the top or at the bottom of a post’s content</li>
<li>Background color – Choose a background color for the message</li>
<li>Text color – Choose a text color for the message</li>
<li>Custom CSS – Add custom CSS rules to the message box</li>
</ul>

DX Out of Date

Display a notification box on the single view of your outdated posts, given a set amount of time (configurable).

WP BrowserUpdate vs DX Out of Date