How To Protect Your WordPress Theme Against Upgrades

Problem: You’ve finally found a theme you like but you want to modify it. The modifications are pretty simple but what happens when you want to upgrade the theme? Do you really want to go through all those files again hunting down the changes? Don’t you wish you could just upgrade and be done with it?

I’ve been there. I’ve done everything the wrong way at least twice. Learn from my mistakes. Here’s the right way to modify your theme and protect it against any future upgrades. And don’t worry, it’s really simple. As it usually turns out, WordPress is ready for us and has done most of the heavy lifting.

Create a Child Theme for Simple Modifications

Did you know you can make CSS-only themes for WordPress? CSS-only themes pumped up with the power of custom PHP in functions.php? I don’t know why more people don’t know about this feature of WordPress or use it more often. It’s really powerful and clean and—more importantly—solves probably 99% of all your theme modification needs.

In wp-content/themes make a new folder called “sample”. Or “monstermonkey” or something. Try and make it unique. In that folder we’re going to make a file called style.css. Just like a regular WordPress theme. I’ll give you all the code for your style.css file straight up (adapted from the WordPress codex) and we’ll break it down afterwords. Here’s the code:

Theme Name: Sample Theme
Theme URI:
Description: Testing WordPress Child Themes
Author: Your Name
Author URI:
Template: thematic
Version: 1.0
This work, like WordPress, is released under GNU General Public License, version 2 (GPL).

@import url('../thematic/style.css');

a:link {
    color:red; /* Red? Ugh! */
a:visited {
    color:green; /* Green? Yechh! */

The most important thing in this stylesheet is Template: thematic. This tells WordPress to use all the template files from another theme. In this case Thematic. But it could just as easily be cutline, default, sandbox, or anything—as long as it matches the folder of the Parent Theme, all in lowercase. The WordPress codex calls this defining a Parent Theme. Thusly: Child Themes. You just made one.

Next we’re going to import the stylesheet of our Parent Theme. Thanks to relative links and WordPress naming conventions this is insanely easy.

@import url('../thematic/style.css');

The ../ is the most important thing here. It means move up one directory level. This gives us the power to import the stylesheet of any theme in our wp-content/themes directory. While this is fun for making weird theme mashups (try defining classic as your parent theme and importing the default stylesheet) the real power of this technique comes in protecting your favorite WordPress theme from upgrades.

You can now edit the CSS of your favorite theme without touching the original file. This is the real power of Child Themes. And it’s huge.

WordPress Child Themes are THE best way to make custom CSS changes to your themes.

In the example above I’ve made a pretty broad declaration about links changing the links to red (ugh!) and the visited links to green (yechh!)—as long as they don’t have very specific CSS declarations made in the original stylesheet. But what if you want to change the menu styles of your theme or the header styles, where more specific CSS declarations are made? This is easy too. Simply copy the offending section of the original theme stylesheet into your new Child Theme stylesheet and—boom!—you can make the changes there, free from worry.

Important note: all this hinges on the Child Theme being the active theme. Otherwise, well, it won’t work. 🙂

Bonus for Thematic Users

If you want to start your Thematic Child Theme the exact same way I do, just copy the Thematic Sample Child Theme included with your Thematic download into your wp-content/themes directory. Simply change the copied folder name and the name of the theme in the copied style.css. Activate it and you’re ready to edit your WordPress theme the smart way.

Choose Plugins That Don’t Require Theme Modifications—Or Use The Right Kind of Theme

Confession time: I’m obviously completely comfortable with modifying WordPress themes but adding code for plugins and messing up my template files just rubs me the wrong way. It’s one more thing I have to worry about when I’m upgrading my site theme. If a plugin requires you to edit your WordPress theme reconsider that plugin. Is it really worth harming the upgrade-ability of your theme just to have that plugin?

Well, yeah. Maybe it is.

OK. Sometimes it is. But I have a solution. Use a different theme. Use a theme that comes ready for absolute must have plugins. Or a fully widgetized theme like Options, Vanilla or Thematic.

A plugin-ready parent theme takes the upgrade pressure off of you. Want Subscribe to Comments in your Theme? Thematic has it (until it moves to core—please!—move it to core!). Want to use Similar Posts in your theme after a single post? Thematic has a widget-ized area right after the single post. Just move the similar posts widget there.

It’s Really Not That Hard to Keep Your WordPress Theme Safe

Reconsidering the value of plugins, using a plugin-ready theme and using a fully widget-ized theme will make your theme upgrades a whole lot simpler. Add all that up with the power of Child Themes and you’re set.

Author: Ian Stewart

Design Director on Design at Automattic.

79 thoughts on “How To Protect Your WordPress Theme Against Upgrades”

  1. Excellent advice, Ian. Especially suggesting that better WP themes upgrade more easily. Plugins should use wp_head() wp_footer() and official WP hooks/actions when modifying your blog.

    Well, I better get to work on finishing up 1.6. 😉

  2. Good article Ian. I’m in the middle of a major redevelopment of how my Options theme works. I definitely didn’t make it “upgrade friendly.” So, that’s what the new development is all about.

    I don’t like adding plugin code in theme files either, but it’s a necessary evil sometimes.

    I’m glad you figured out the parent/child theme thing. I might have to use it one of these days. Or, just start designing child themes for you. 😉

  3. This is a great article.

    And this feature in WordPress could be very useful for theme authors as well, as there are many who really just ad a new style to the default, classic or another theme they find that they like.

  4. @Scott Funnily enough, I hadn’t noticed 1.6 wasn’t out until I started writing this post. I love svn.

    @Justin I haven’t exactly figured out how to make WordPress recognize new custom page templates yet, particularly for the front page. So no, I haven’t figured that out yet. But I have come up with a way to produce custom front pages with child themes—as long as there is a front page template in the Parent Theme. I haven’t decided if that’ll make it into Thematic though.

    @Kristen Exactly! 🙂

  5. Adding a note that the newly created child theme is the one that should active might help new users 🙂

  6. Pingback: Using Child Themes
  7. I’ve seen the “Template:” thingy mentioned before, with very little explanation. So, thanks for enlightening me, Mr Stewart.

  8. Dear Ian,

    I absolutely LOVE your Thematic theme. I just downloaded it and plan on using it for my site. Based on your article, I’d day Thematic is a great theme for protecting my wordpress theme against upgrades no?

    I plan on making some modifications to the look. Will let you know how it pans out.

    Thanks again!

  9. Hi Ian

    I love the idea of adding a Home link to the menu but I’ve followed your instructions and am having no joy.

    Unfortunately, I can’t provide a link as I’m modifying your Thematic them locally before going live.

    Btw, it’s a great theme… many thanks.


  10. That’s probably because I totally forgot to add the line …

    add_filter('sandbox_menu', 'sample_menu' );

    Sorry. Check it over again.

  11. Well… I’m a newbie jumping in with some old hands here, so apologies if my questions seem somewhat naive. I’m new to WordPress, but after lots of research, I’m keen on writing a child to Thematic to launch our blog. So first off: you and folks like you have done a great service to the community by working in this manner – kudos! My questions:
    1. First, you reference your parent theme’s style sheet. Then you add your new definitions. Those definitions are either added to your parent theme’s style sheet, or, if in conflict with them, given priority. Is this correct?
    2. If this is correct, why is it also necessary (or at least, recommended) to add those additional import lines referencing Thematic’s /library directory. Are these not automatically inherited, too?
    3. On a slightly different topic, would one attempt to make changes in these types of files in the same manner that one would work on a normal website (for example, by loading them into Dreamweaver or a similar app)?

  12. Minor point – looks like you’re missing the closing tag for the anchor, so the line should read:
    $menu .= get_option(‘home’) . ‘/” title=”Home”>Home‘;

    With that, and the change you mentioned in the forum (sandbox_menu has changed to globalnav_menu as of thematic 0.7), it works brilliantly!

  13. Can I just say, WOW.

    I’m new to wordpress, HTML and FTP programs. I’ve come over from blogger where everything is done for you. I’ve been wondering around pretty aimlessly trying to do what I want to do but not knowing how. I put in a font question over in support and I don’t know if it was you who referred me here or someone else, but they’re a life saver!

    I am just super impressed with this web site. Thanks for this wonderful website.

  14. Ian — Just wanted to let you know that I’m in the middle of creating a child theme locally for RawTake (dot net) using Thematic. So far, so good. I’ll be diving deeper into the forums and articles to help guide me more and as soon as we launch, I’ll let you know 🙂 Would love to get your thoughts. Thanks again for this article and many others.

  15. Thanks for the information. I have created a theme child for “tarski”, and I also chose my theme child from the Appearance page in admin. I was also able to see a template I had there in my “Write Page” page in Admin. But the site does not recognize my “style.css”.
    My CSS file is defined this way (which I think is correct):
    Theme Name: Sourena
    Theme URI:
    Description: Child Theme for Tarski
    Author: Sourena Mohammadi
    Author URI:
    Template: tarski
    Version: 2.4
    This work is released under the GNU General Public License (GPL), version 2:
    @import url("../tarski/style.css");

    What am I doing incorrectly?

    1. You need to import the style sheet from the parent theme. So It needs to be this
      @import url(‘../thematic/style.css’);
      rather then what you’ve got
      @import url(“../tarski/style.css”);
      ../ goes back out of a folder or directory. So right not you are going out of your child directory(../) and then back into you child directory(/tarski)
      Or have you renamed the thematic theme to tarski?

  16. Thank you for the insightful article. I have some dentist friends that are considering starting a WP site and I’m sure they probably haven’t thought “down the road” far enough to think about avoiding “re-work” (or worse) as far as upgrades. I will be forwarding to them so they can “think ahead” on this item…Thanks again!

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