Support » Fixing WordPress » READ THIS FIRST – WordPress 4.5 Master List

  • Moderator James Huff


    Volunteer Moderator

    Hooray! Coleman is here! But OMGWTFBBQ!? WordPress 4.5 broke everything?

    Don’t Panic!

    Before you go any further, make sure you’ve updated your plugins and themes to the latest versions, clear your browser’s cache and cookies and re-log into your WordPress dashboard.

    Still having problems? Okay, read on!

    This thread contains the known issues with plugins and themes found in 4.5. Please read this WHOLE topic and come back and check again later, as it will be updated.

    Remember to be calm, be patient and be respectful. Volunteers are out here to try and help you, but we need your help too. All of the normal forum rules still apply. Remember, you are just as important as everyone else.

    If your post doesn’t show up right away, please be patient. With the higher than normal post volume, more posts get flagged as spam by our auto-spam tool. We’re working hard to keep the queue clear, but making multiple posts slows us down, as we have to go back and check if you already posted. Post once.

    • Do use proper capitalization in post titles and body. Punctuate your sentence properly and humanely, it helps us read.
    • Do use descriptive subject lines. “All permalinks broken since 4.5” is much better than “Augh! Help ASAP! This version is terrible!”
    • Do describe the problem clearly. Explain what you’re seeing, include error messages and link to screenshots if needed. Linking to your site, if the problem is on the front-end, also helps.
    • Do be patient. We know it sucks to be down, but posting multiple times doesn’t get you help any faster.
    • Do make your own topic unless you are using the exact same version of WordPress on the same physical server hosted by the same hosts with the same plugins, theme and configurations as the original poster. You may find it weird, but it will be easier for us to help you specifically if you have your own topic.
    • Do mark your topic as resolved when it’s fixed so we know not to come looking there anymore.
    • Do remember you’re not alone.

    Also keep in mind that not liking the direction of WordPress’s design does not a bug make. If you don’t like a feature, please don’t make a series of posts complaining about it. Look and see if someone already did, and post there, or consider joining the process earlier on (like in Beta or even test via SVN). What you’re seeing today is the result of thousands of hours of work and testing, and unless something is outright broken, it’s highly unlikely to be changed.

    Again, before you post:

    Make sure you’ve read the entire Master List post and New Features in 4.5 Codex Article.

    Go to your own install’s about page – – to see what’s new.

    And then make sure you’ve tried…

    • Flushing any caching plugins you might be running, as well as server and/or browser caches. Not just your browser, but any op cache or content network cache as well such as Cloudflare. That will solve many weird Javascript issues.
    • If your host provider has a “Purge Varnish” option or if you can ask your provider to flush memcache on your server.
    • Deactivating all plugins (yes, all) to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s). If you can’t get into your admin dashboard, try resetting the plugins folder by FTP or PhpMyAdmin (read “How to deactivate all plugins when you can’t log in to wp-admin” if you need help). Sometimes, an apparently inactive plugin can still cause problems. Also remember to deactivate any plugins in the mu-plugins folder. The easiest way is to rename that folder to mu-plugins-old
    • Switching to the Twenty Sixteen theme to rule out any theme-specific problems. If you can’t log in to change themes, you can remove the theme folders via FTP so the only one is twentysixteen. That will force your site to use it.
    • Manually upgrading. When all else fails, download a fresh copy of the file of 4.5 (top right on this page) to your computer, and use that to copy up. You may need to delete the wp-admin and wp-includes folders on your server (NOTE: do not delete the wp-content directory or your wp-config.php file) Read the Manual Update directions first.
Viewing 6 replies - 1 through 6 (of 6 total)
  • Moderator James Huff


    Volunteer Moderator

    Core Changes

    In addition to new features highlighted in the release post:

    Updated libraries: We updated jquery, backbone, and a couple other libraries. This may cause your browsers to render oddly. Please remember to flush your cache (browser and website/server). If you’re using Cloudflare, you may need to kick it.

    REST API: There was a breaking change in the REST API that could potentially break plugins that use it. If you’re not using a plugin to connect with the API, don’t worry. If you are, check out the Core Post on the subject.

    Moderator James Huff


    Volunteer Moderator

    Not a Bug

    The following features changed behavior.

    Linking in Posts: The link interface has changed. Now it’s a smaller, inline tool that does a better search. Just start typing in your existing post title, and it will show up. If you miss the old interface, click the gear icon.

    Formatting Shortcuts: We already had lists and headings. Now we’ve included horizontal lines and code too. Your text magically changing is intentional.

    Image Quality: Yes, we changed it. It shouldn’t impact most people, but we’re trying to make WordPress render faster. If you happen to be a photoblogger and desperately need it back, please check out the following plugins

    You can, of course, add code like this to your site, however we think most people would like that slider more than guesswork. Just change 100 to the percentage you’d like to render as:

    add_filter( 'jpeg_quality', 'worg_support_image_quality' );
    function worg_support_image_quality() {
        return 100;

    The old setting was 90 and the new is 82. (Please read the proposal to fully understand the research and decision.)

    Embedding WordPress: You can now embed a front page of a WordPress site in another WordPress site.

    The following features are new, but may not show up on all sites.

    Custom Logo: This feature is only available on themes that have implemented it. If you don’t see it, check out TwentySixteen.

    Warning messages where there were no warning messages before: The WP Database code no longer suppresses warning messages. This is intentional, in an effort to help users and hosts find problems with their configurations. However, normal production systems should not be displaying warning messages in any case. Check your wp-config.php file and make sure that the WP_DEBUG setting is set to “false”, and also check that your hosting system has the PHP “display_errors” setting disabled. Debug messages are for testing, not live systems.

    Moderator James Huff


    Volunteer Moderator

    Known Issues

    • When using the code formatting shortcut a race condition (i.e. things happening at the same time) may occur that prevents the text from converting as intended. (See ticket #36459)
    • Image uploads may fail on servers with an older version of Imagick. (See Trac ticket #36534) Note: while a fix for WordPress is in progress, updating Imagick on the server is also a solution.
    • Some sites may experience their browser stating they have an infinite redirect loop on the front page of their site. – Go into Settings > General in the admin dashboard and make sure the URLs there are all lower-case (See Trac ticket #21602)
    • The new inline link editor fails in Firefox and Chrome after Advanced Options is used once. (See Trac ticket #36732)
    • The bundled Twenty Eleven theme has some styling issues for pages with sidebars (See Trac ticket #36510). Fixed in WordPress 4.5.1
    Moderator Ipstenu (Mika Epstein)


    🏳️‍🌈 Advisor and Activist

    Issues with Plugins

    • Visual Composer – Please upgrade to 4.11.2+. The compatibility issue was fixed in Version 4.11 on March 10th:
    • Custom Facebook Feeds – Breaks JavaScript rendering. Fixed in
    • Jetpack – Please make sure you’re connected to Jetpack if you use Photon. Not being connected will cause your images to not display. (nb – this is not a Jetpack or 4.5 bug, just something people are noticing right now)
    • XpertAccordian – A premium plugin. It’s not working with the editor due to Javascript updates.
    • a3-lazy-load – Causing images not to show
    • HeadSpace2 – jQuery 1.12 problems as outlined below
    • Beaver Builder plugin – Some reports of CSS issues causing media libraries to not work. More info here:

    Issues with Themes

    • Divi
      Divi Version 2.7.3 ( updated 04-13-2016 ) fixes the jQuery issue outlined below. Update your theme.

      Exhibits the jQuery problem as described below. The file js/custom.js has the issue on line 706. Adding double quote marks around the hash symbols (#) will fix it.
      Change this:
      $( 'a[href*=#]:not([href=#])' ).click( function() {
      To this:
      $( 'a[href*="#"]:not([href="#"])' ).click( function() {
      Alternatively, check with your theme vendor for an update.

    • Other Themes on Themeforest – Lots of themes from Themeforest are exhibiting this issue. If you have a theme from there, please contact your theme author for an update to fix any instances of the jQuery problem as listed below.

    List of known Themeforest themes with the problem:

    Issues Elsewhere

    • Users with WordPress installed under Plesk may note a Forbidden error quoting wp-tinymce.php. The solution for this is covered on Plesk’s support site.
    Moderator Samuel Wood (Otto)

    (@otto42) Admin

    jQuery 1.12 problems

    WordPress includes the latest version of jQuery 1.12, which was released back in January:

    It has been discovered that old versions of jQuery worked with an incorrect syntax. That bug was one amongst many bugs fixed in jQuery 1.12. The symptom of this problem is the following message (or something very similar) in the Javascript console when viewing the site in a browser:

    Uncaught Error: Syntax error, unrecognized expression: a[href*=#]:not([href=#])

    This is a bit of code that is in somewhat common usage. The problem is that it is incorrect. The link location (hash marks, #, in this case) should be quoted: a[href*="#"]:not([href="#"])

    Another example would be a[href=#scroll-to-top] which, when written correctly, should be a[href="#scroll-to-top"]

    This can happen in other ways too, this is just one commonplace example. The signs that distinguish this problem are the href and the hash mark (#).

    So, what a lot of people are finding out now is that a whole lot of Javascript code out there was doing-it-wrong all this time, and they never noticed because jQuery incorrectly worked with that particular style of broken code. Once WordPress upgraded, and people got the new jQuery, people are now seeing those bugs in their own code.

    All that broken Javascript code will need to be fixed. Fortunately, it’s a pretty simple fix, but in the meantime, it’s still broken.

    The best advice we can give you is to update all your plugins and themes to the latest versions by their vendors. Plugin and theme authors should be looking to the JS libraries they use for fixes, and including those newer versions of the affected libraries in their code.

    Moderator Samuel Wood (Otto)

    (@otto42) Admin

    MySQL error messages

    Previous to WordPress 4.5, error messages and other warnings that originated in the PHP and MySQL database systems were being suppressed, or hidden from the users. On the whole, this is not a great solution for long term, because while the systems usually “work” even with these types of errors, it is better to find and fix errors when they exist.

    So, WordPress 4.5 removed the error suppression code from the database system. This may cause assorted warnings that you did not previously see. It is important to understand that WordPress 4.5 did not *cause* these warnings, it simply stopped hiding them from you like previous versions did. The errors were already there.

    It is also important to note that these particular issues are rare. Uncommon. They only happen with very specific conditions, usually in older hosting environments. The easiest way to fix them may be to simply have your host update your hosting service to a newer server, or to migrate to a better hosting system in some manner.

    Here’s some of the types of warnings we’ve seen so far, with instructions on how to fix them. Note that fixing these types of issues in your server configurations may not be the easiest thing in the world. You may need help from your hosting service.

    Warning: mysqli_real_connect(): The server requested authentication method unknown to the client [mysql_old_password]

    Your MySQL server appears to be old, or is otherwise using “old passwords”. The mysqli client does not support old passwords. WordPress uses the mysqli client preferentially when PHP 5.5 or higher is available on the hosting software.

    Ideally, you need to modify your MySQL server to use the “new password” format. This isn’t really “new”, it’s been around for 10 years, however some servers are configured to use old password hashes still, to this day.

    There’s various articles on how to do this around the web, however, you will probably need to ask your host to do this for you, or to migrate your database to a newer MySQL server instead. However, if you have the ability to fix your server, here are some example articles on the topic:

    That would be the correct way to do things. It is also more secure. You want your MySQL server to be using better password hashes.

    If you need a quick-fix instead, then add this to your wp-config.php file. This will force WordPress to use the old, deprecated mysql client. You should avoid this long term, since the mysql client will not be supported in later versions of PHP.

    define('WP_USE_EXT_MYSQL', true);

    Warning: mysql_connect(): Headers and client library minor version mismatch

    This is caused by a mismatch between the mysql libraries that your PHP installation is using and the mysql client libraries installed on your actual system. This can be resolved by switching PHP to use the “ND” (Native Driver) version of these libraries. These ND versions have the client included with the library and so don’t have that external dependency that can cause this version mismatch error.

    How you switch to using the ND versions depends on your hosting system. If you’re on a shared host, then you need to tell them about it and have them fix it for you.

    The most recommended fix would be to see if your hosting provider provides a newer version of PHP. Most providers have some means for you to select the version of PHP that you want to use. Simply updating your PHP version to a more recent one will often fix the issue. We recommend selecting the latest version of PHP available to you. This would usually be PHP 5.6 or PHP 7.0. (Bonus! Using a newer PHP makes your website run *much* faster too!)

    If you have access to a cPanel for your hosting system, then check in the PHP Selector that you are using the nd_mysql and nd_mysqli libraries, and not the basic mysql and mysqli ones.

    If you have control over the server, then you can use your preferred package installation system to remove the php5-mysql packages in favor of the php5-mysqlnd ones instead.

    More information:

    WP4.5 upgrade mysql_connect() error

Viewing 6 replies - 1 through 6 (of 6 total)
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