Why Contact Form 7 does not work on iOS

Recently, on the WordPress site, I noticed the problem of sending messages via Contact Form 7 from devices with the iOS operating system.
If you used Google reCAPTCHA, when you clicked on the Send button, the page was updated for a very long time and reCAPTCHA reported a wait error, if you disable reCAPTCHA, then the message was sent after 1-2 minutes.

As it turned out, iOS somehow started blocking AJAX, which was used by default when updating the page.

So to solve the problem, I opened the configuration file wp-config.php and just before the line:

define('WP_DEBUG', false);

Added a line:

define ('WPCF7_LOAD_JS', false);

This line prohibits Contact Form 7 from using Javascript.
If you specify this variable at the end of the file, it will not work.

After this, the messages on iOS started to go immediately.

How to remove “Proudly powered by WordPress”

To remove the inscription «Proudly powered by WordPress», which is usually displayed at the bottom of each page, you need to edit the footer.php file of the active theme (for example, if the twentyfifteen theme is active, then /wp-content/themes/twentyfifteen/footer.php).

Namely, clear the content between the following tags:

<div class="site-info">
...clear what's here...
</div><!-- .site-info -->

Also noticed that if you use Jetpack with infinite scrolling, then it adds its footer, to open it you will open the file /wp-content/plugins/jetpack/modules/infinite-scroll/infinity.php and delete the line:

<?php echo $credits; ?>

The AMP plug-in’s footer is here – /wp-content/plugins/amp/templates/footer.php.

After updating the theme or Jetpack may have to repeat.


How to change a WordPress theme through MySQL

To change the WordPress theme via MySQL, first see what theme is specified at the moment, for this, execute the SQL query via phpMyAdmin or MySQL client:

SELECT * FROM wp_options
WHERE option_name = 'template'
OR option_name = 'stylesheet'
OR option_name = 'current_theme';

Next, see what themes are in the /wp-content/themes/ directory.

For example, to change to the standard Twenty Fifteen theme, let’s execute three SQL queries:

UPDATE wp_options SET option_value = 'twentyfifteen' WHERE option_name = 'template';
UPDATE wp_options SET option_value = 'twentyfifteen' WHERE option_name = 'stylesheet';
UPDATE wp_options SET option_value = 'Twenty Fifteen' WHERE option_name = 'current_theme';

How to disable the WordPress plug-in via MySQL

To disable all WordPress plugins via MySQL, you must:

1) Be sure to make a backup copy of the database.

2) Open the phpMyAdmin or MySQL client from the terminal:

mysql -u USER -p

3) Execute the SQL query (if necessary, specify the correct prefix wp_):

UPDATE wp_options SET option_value = '' WHERE option_name = 'active_plugins';

After that, all plug-ins will be disabled and you can activate them again one by one in the admin panel.

You can also temporarily disable the plugin by renaming the directory with its files, the plugins are in the /wp-content/plugins/ directory.

How to remove W3 Total Cache plugin from WordPress

To uninstall W3 Total Cache from WordPress, you need:

1) In the plugin menu, click the cache clear button.

2) Deactivate the plugin in the plugins menu and click “Delete”

3) In the root directory of the site, at the beginning of the wp-config.php file, if left, delete the lines:

/** Enable W3 Total Cache Edge Mode */
define('W3TC_EDGE_MODE', true); // Added by W3 Total Cache

/** Enable W3 Total Cache */
define('WP_CACHE', true); // Added by W3 Total Cache

4) As I noticed after the plug-in there are a lot of files, and on large sites there can be millions of files with cached data.
In the wp-content directory, delete the files, if any, advanced-cache.php, object-cache.php, w3tc-config and cache (here cached data).