If you’ve been getting “Deprecated function” warnings on your WordPress site, we get it, it looks weird and makes you think something is seriously wrong. Especially when the site is still loading fine, and you have no idea where that message even came from.
But here’s the thing — these aren’t really “your site is broken” type errors. They’re more like WordPress giving you a heads up that some code is getting outdated and might cause problems later.
That said, don’t just leave it. Here’s what’s going on and how to deal with it.
Why do these errors show up?
These usually start appearing after a WordPress update. WordPress keeps improving its code over time, and when it does, some older functions basically get retired. If a plugin or theme you’re running is still using those old functions, and boom, you start seeing the warnings.
So basically, your site has new WordPress code on one side and older plugin or theme code on the other, and they’re not fully on the same page anymore.
WordPress Deprecated Function Errors? Here’s How to Fix Them.
Here are a few things that you need to look for:
Turn Off Error Display (Quick Temporary Fix)
If these messages are showing up on the actual front end of your site, hide them first. Not because you’ve fixed anything, just because your visitors don’t need to see that stuff.
Go into your wp-config.php file and turn off debug display. That’s it. The problem is still there, but at least your site looks normal while you sort it out.
Update Everything First
Seriously, do this before anything else. Update your plugins, themes, and WordPress itself.
A lot of the time, the developer has already pushed a fix, but you just haven’t updated yet. So a simple update could make the whole thing go away without you having to do anything else.
Refresh your site and check if the errors are still there.
Find the Source of the Error
Still showing up? Then you need to figure out where it’s actually coming from.
The error message usually gives you something to work with. It’ll often mention:
A plugin name
A theme file
Or a specific function
You don’t need to understand the whole thing. Just look for anything that sounds familiar and go from there.
Check Plugins and Themes
Nine times out of ten, it’s a plugin or theme that’s been sitting there without updates for too long.
Start turning off plugins one at a time and refreshing the site each time. When the warning stops showing up, that’s your problem plugin right there.
Do the same thing with your theme, switch to one of the default WordPress themes, and see if that clears it up.
Replace or Remove Outdated Plugins
Found the plugin causing it? If it hasn’t had an update in a long time, just replace it. It’s not worth keeping around.
Outdated plugins don’t just cause warnings — they can open up bigger problems over time.
Find something that does the same job but is actually being maintained.
Fix It Manually
If you’re decent with code, you can go in and swap out the deprecated function for the current one. WordPress docs will usually tell you what to use instead.
But if you’re not sure what you’re doing, leave this alone. Genuinely. One wrong edit and you’re dealing with a broken site on top of everything else.
When to Ignore It (And When Not To)
If it’s only showing in the backend or you’re in a dev environment, it’s not urgent. The site is still working, and no one else is seeing it.
But if it’s on your live site or the warnings keep growing, pay attention to that. It won’t blow up overnight, but it will catch up with you eventually.
Final Thoughts
These errors are mostly a future problem, not a right now problem. Your site can run totally fine with them for a while. But they’re worth cleaning up before they turn into something worse.
Most of the time, just staying on top of updates and ditching outdated plugins is enough to keep you out of this situation entirely. That’s where proper website maintenance and a WordPress support agency really help. Staying on top of things keeps your site running smoothly and performing really well.
