How to Upgrade jQuery to the Latest Version in WordPress: An Expert‘s Guide

As a WordPress site owner, keeping jQuery up to date is crucial for performance, security, and leveraging the latest features. With over 15 years of experience as a web developer, I‘ve seen firsthand how problematic outdated jQuery can be.

In this detailed guide, you‘ll learn how and why to upgrade jQuery to the most recent version. I‘ll also provide troubleshooting tips to handle any issues based on my experience managing WordPress sites for clients.

A Brief History of jQuery

Since its launch in 2006, jQuery has become one of the most widely used JavaScript libraries. Today, it powers interactive elements on over 73% of the top million websites.

Over the years, the jQuery core and APIs have evolved through several major releases:

jQuery 1.x

• v1.0 (2006) – First stable release

• v1.3 (2009) – Significant performance improvements

• v1.7 (2011) – Lighter footprint, deprecated features removed

jQuery 2.x

• v2.0 (2013) – Dropped IE 6-8 support

• v2.1 (2015) – Browser bug fixes

jQuery 3.x

• v3.0 (2016) – No more support for older browser versions

• v3.4 (2018) – Security patches, bug fixes

• v3.6 (2022) – Latest version with improvements

Over 300 open source contributors have developed jQuery into the mature library it is today.

jQuery Usage Statistics and Trends

As an experienced web developer, I closely track jQuery usage metrics and trends:

• Used on 73% of the top million websites as of 2022.

• Down from 83% of the top 10 million sites in 2016, as alternative frameworks gain adoption.

• However, still used on over three-quarters of all WordPress websites.

• Growth of JavaScript front-end frameworks like React has impacted jQuery usage, but many sites still rely on jQuery.

• The need for a cross-browser DOM manipulation library persists, especially among non-JavaScript developers.

While newer frameworks get a lot of attention, jQuery remains the most widely used JavaScript library. But growth has stagnated – to leverage new features and security updates, sites should keep jQuery current.

The Risks of Outdated jQuery Versions

Allow me to emphasize from experience – outdated jQuery contains vulnerabilities that can endanger your website:

• Security issues – Using vulnerable jQuery opens the door for cross-site scripting, denial of service attacks, and other exploits.

• Broken functionality – Out-of-date jQuery may break certain interactive elements relying on newer methods.

• Performance lags – Improvements in newer jQuery versions speed up DOM manipulation and effects.

• Compatibility problems – An outdated codebase won‘t work well with the latest browser versions.

• Unused optimizations – Missing optimization and bug fixes slows down jQuery performance.

Keeping jQuery up to date is a vital website maintenance practice. Don‘t let your site get left behind on an unsupported version.

How Long Will Outdated jQuery Versions Be Supported?

jQuery follows the prevailing web standards policy of only supporting current and the previous major release.

For example, when jQuery 3.0 was released, support ended for jQuery 1.x versions.

Currently, the jQuery team only supports jQuery 2.x and 3.x. So jQuery 1.x has been unsupported since 2016.

Once jQuery 4.0 comes out in the future, jQuery 2.x versions will lose official support.

I don‘t recommend sticking with an unsupported jQuery release more than a year after it goes end-of-life. Lack of patches for newly discovered vulnerabilities in old jQuery versions poses security risks.

Best Practices for Updating jQuery

Based on my experience managing WordPress sites, I recommend updating jQuery at least once a year, and even more frequently for high traffic sites.

Follow these best practices when upgrading:

• Test first on a staging environment – Updating any JavaScript library can potentially cause conflicts, so test on a copy of your site before updating production.

• Reviewchangelog – Glance through the release notes for each jQuery version to look for new features or breaking changes.

• Update incrementally – Move up one major version at a time, testing each step of the way, rather than jumping multiple versions.

• Limit customizations – The more your jQuery is customized, the more likely an upgrade can break something. Keep customizations minimal.

• Monitor notices – Watch the console for deprecation notices – they indicate things that will break in future versions.

• Consider timing – Avoid changing jQuery versions right before big launches or traffic events, in case something goes wrong.

With proper precautions, you can upgrade jQuery seamlessly. But it pays to be careful, methodical, and well-tested when changing versions.

Step-by-Step Guide to Upgrading jQuery in WordPress

Once you decide it‘s time to update jQuery, the actual process is straightforward:

Check Your Current Version

Use the following to check the installed jQuery version:

jQuery.fn.jquery

This will output the current version in the console. Compare it against the most recent stable release.

Choose Your Upgrade Method

You have two options to upgrade jQuery:

1. Use a plugin like jQuery Updater

2. Manually replace jQuery .js files in wp-includes/js/jquery/

For most users, a plugin like jQuery Updater is simpler. But manually replacing the files gives you more control.

Update jQuery Migrate

Don‘t forget to also update the jQuery Migrate plugin to the latest version to handle any backwards compatibility issues:

https://code.jquery.com/jquery-migrate/ 

Test Extensively

With the new jQuery version installed, thoroughly test:

• Site pages/posts – Check all navigation, widgets, media, effects

• Interactive elements – Dropdowns, accordions, sliders, menus

• Plugins – Verify full compatibility

• Browsers – Test in all browsers your site supports

Troubleshoot Issues

If you encounter functionality issues or conflicts with the new jQuery version:

• Switch back to previous version as a test.

• Try updating jQuery incrementally from your old version.

• Disable plugins and switch WordPress themes to isolate issues.

• Search jQuery documentation and plugins forums for fixes.

With some targeted troubleshooting, you can resolve most upgrade issues.

Stay Up to Date

I recommend setting a calendar reminder every 3-6 months to check your jQuery version. Outdated jQuery can quickly become a liability.

Why You Should Always Upgrade Outdated jQuery

Failing to update jQuery is like driving a car without changing the oil – it may run fine for a while, but eventually it will break down.

As a WordPress expert, I‘ve seen many site owners run into problems by sticking with outdated jQuery:

✘ Security vulnerabilities

✘ Bugs and broken functionality

✘ Performance and speed regressions

✘ Conflicts with new browser versions

✘ Missing out on new features and improvements

So stay proactive about keeping your jQuery version up to date. It takes a little extra care, but pays off by keeping your site running its best.

In Summary

I hope this comprehensive guide provided you a deep look at why and how to upgrade jQuery in WordPress. Here are some key takeaways:

• jQuery is still used on over 3/4 of WordPress sites, so keeping it updated remains important.

• Vulnerabilities and lack of support for outdated versions makes upgrading jQuery vital.

• Test upgrades on staging before updating production to avoid conflicts.

• Troubleshoot issues methodically if anything breaks after updating.

• Set periodic calendar reminders to check jQuery so it stays current.

Please let me know if you have any other questions!