This Plugin Pollutes the Error Log with Multiple Deprecated Notices

Hi,

Thank you for developing the plugin. I’ve noticed an issue where the plugin generates multiple warnings in the error log.

When clicking the “Save changes” button on the plugin’s settings page, the following warning is logged in the wp-content/debug.log file:

PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 143
PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 144
PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 145
PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 146
PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 147
PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 148
PHP Deprecated:  Constant FILTER_SANITIZE_STRING is deprecated in .... /wp-content/plugins/minify-html-markup/minify-html.php on line 149

This issue seems to occur with PHP 8.1. If you would like to see the related documentation, please click the following link:
/manual/en/migration81.deprecated.php

Although this may not currently break functionality, the repeated logging unnecessarily pollutes the error log and could make debugging other issues more difficult. Since the plugin’s description states compatibility with “PHP version 5.2.4 or higher,” this behavior does not align with that promise.

Could you please investigate this issue and update the plugin for compatibility with PHP 8.1?

Let me know if you need any additional details.

Thank you!