So how do you update old versions of WordPress? The short (tongue in cheek) answer to this is… ‘very carefully’.
Updating an old WordPress site needs to be done in stages. Unfortunately you can’t just update to the latest version and magically expect everything to still work.
Here’s a guide to how we approach this.
How Old Is an Old WordPress Site Really?
The first thing to figure out is just what you’re dealing with. The WordPress version itself is just one piece of the puzzle.
Theme & Plugins
The other key parts of WordPress are the theme and the plugins.
All sites have one theme, but some also use a child theme which is the proper way to apply customisations to it’s main (or parent) theme. You need to know how old the main theme or parent theme are, and if there are updates available for it. You also need to be aware that if a child theme does exist then you may need to make code changes to keep it working.
Plugins are likely to be a major piece of work to update. You need to know what is actually being used, what is already updated, what needs updating and what is no longer supported. That last category can be tricky. If a new version of a plugin hasn’t been released in years then it’s no longer supported, may no longer work when you update other things and may even have security holes in it.
php & MySQL
Then there is the technology behind WordPress.
The programming language that WordPress is written in is called php. If the WordPress version is very old, it’s likely the php version is also old and no longer supported (which is a security risk). More recent versions of WordPress now even warn you about this (with a message saying “your php version requires an update”).
There is also a database where all of your WordPress content and settings are stored. The database software that lives on your web server is called MySQL (or MariaDB). Your hosting company may have upgraded MySQL over the years but many get lazy with this, because it’s not straightforward, and just leave you on old versions unless you push them!
The latest WordPress will still work on these old versions of php and MySQL, but they will eventually stop supporting them. The current WordPress will now warn you about this with a message saying “your php version requires an update”.
You can see the current WordPress requirements here. They currently still support php 5.6 (released in 2014) but recommend 7.4+, and support MySQL 5.0 (which dates from 2008) but recommend 5.6+.
You might ask why bother upgrading these if they still work? In the case of php, two main reasons – modern versions are much faster, and versions older than 7.4 are no longer supported. Similarly for MySQL, modern versions are much more efficient with memory and disk usage which can make things a lot faster and more stable for your website.
Bottom line: it’s important to know your starting point with all of this to better understand what’s involved.
[If this is all starting to sound a bit painful – we do provide a service to update very old WordPress sites]
Can You Update a Live Website?
You can apply updates directly to a live site, but I wouldn’t recommend it. The chance of things breaking is very high.
We always start with a full backup, and then work on a copy of the website on a development server. We then fix problems and take backups at various stages as we go. Once all the updates are complete and the site has been properly tested, only then do we copy that working updated version of the site back to your live web hosting.
What To Update First?
It can feel a bit chicken or egg – do you update plugins, php or WordPress first?
The official WordPress way for manual upgrades says to deactivate your plugins before upgrading, then upgrade WordPress and then install new versions of your plugins.
But we find the process is generally smoother if you upgrade your plugins and theme as far as they will go. Then upgrade WordPress (in stages – more on that shortly). Then upgrade plugins and theme again if needed, and repeat.
Once those updates are fully completed and any unsupported plugins/themes have been replaced, then upgrade your php version. This may then reveal more plugin updates (some plugins now require php7+). And finally work with your web host support to upgrade MySQL if need be.
Updating Old Plugins
Getting plugins up to date will go a lot easier if you audit what you have first, and identify everything that isn’t being used. We always clean up old WordPress plugins before proceeding any further.
Identifying Unused Plugins
If a plugin is not active then it’s clearly not being used – those are the easy ones.
Old WordPress sites tend to build up a collection of plugins that ‘somebody installed at some point’ and nobody can remember why. Identifying which of these aren’t actually in use despite being enabled can be tricky.
One ‘not so subtle’ way to identify unused plugins is to disable them. If they provide a very obvious function it’s easy to see if that function disappears from the website – e.g. if it adds social media buttons and the social media buttons are still there after disabling it.
Another way is to just look at the settings page for the plugin – has it ever been set up? I’ve seen Google Analytics plugins that have been installed for years, but nobody ever added the site ID to the plugin settings meaning it’s clearly not being used. Or backup plugins where a backup has never been taken.
One other useful way, if a plugin works just by using shortcodes, is to search for that shortcode. If the shortcode is designed to be inserted into posts, just use the posts search and search for “[shotcodename” (don’t use a closing bracket as it may have parameters). Similarly you can search the database or theme code.
Deleting all these unused plugins greatly simplifies updating, but also improves things for the users of the site. Typically websites feel faster afterwards – particularly in the admin area. It also can remove a lot of clutter from the admin interface as plugins add side menus, toolbar menus, dashboard widgets, editor buttons and all sorts of junk to the post edit screen. Our clients are often surprised at how much cleaner WordPress looks once all this crud disappears.
Updating What’s Left
Now we’re left with what’s actually in use, we then look at what can’t be updated.
Don’t be fooled by plugins sat there quietly claiming to be up to date! I suspect this is a feature likely to be added to WordPress in the near future, but at the moment a plugin can be 10 years old, have no updates available (because it’s been abandoned by the developer) and not give you any indication that this is a problem.
So you need to check every plugin.
In the plugins page hit the ‘View details’ link for each plugin or check the WordPress plugin directory to see what ‘Last Updated’ says. If it’s more than a few months ago we dig a bit deeper to see if it may have been abandoned recently. If it’s more than a year ago you can be pretty sure it’s been abandoned.
Just because a plugin has been abandoned doesn’t mean it won’t work as you update other things. But for us it’s a red flag because it’s something that may well break a website in future and won’t get security fixes.
Replacing abandoned or unsupported plugins means finding something else that does the same thing. This is typically not hard – just search the plugin directory for what the plugin does (forms, social buttons, comment spam etc). There may even be an alternative version with a very similar name (where a new developer took the old version and created a new plugin from it).
Note: some plugins may not be in the plugin directory. This can be because it’s a custom written plugin especially for this website – in which case code changes could be required. Or there may be premium/paid/pro plugins – these should have updates available (if still maintained) but may need licenses renewing to access those updates.
WordPress Plugins Not Compatible With php7
There are various php compatibility checker plugins for WordPress. These can scan your plugins and tell you if there will be a problem moving up to php7.
These tools may give you a heads up before switching version and can be easier to read for a non-developer than error logs, but anything that doesn’t now work with php7 needs to be upgraded or replaced. WordPress itself will drop support for old php versions sometime soon.
For More WordPress Help Check Out Our Other WordPress How To’s
Updating Old Themes
Themes are very much the core of how a website looks (and possibly functions too). This is starting to change but for old WordPress sites the theme is a major part of the site.
If you’re lucky the theme is still maintained and can simply be updated. You’ll still need to check theme settings for changes and new features that may need adjusting.
However if the theme has been abandoned, there are two options. Go with the current theme and fix any errors that come up. Or switch to a new (maintained) theme which may change the look of your site and require time spent changing settings or creating a child theme to get the look right again.
If you do switch to a new theme I’d recommend avoiding complex themes that try to provide a lot of functionality. Especially those on marketplaces like Themeforest or you’ll likely end up in the same boat again in a couple of years. Keep the theme very simple and let the features come from popular plugins.
Updating Very Old WordPress Versions
In theory WordPress can cope with you upgrading from an ancient version to the latest version in one button click.
In practice, it will probably blow up on anything but the most basic WordPress sites.
A safer approach is to update in stages. WordPress themselves say “you should consider upgrading incrementally to avoid potential conflicts and minimize the risks of database damage”.
We take a very cautious approach when updating clients websites and only ever skip one major version. So if we’re upgrading an ancient WordPress 3.5.1 website, then we’ll only upgrade to version 3.7 first. Then let WordPress apply database updates. Then move up to 3.9, then 4.0, then 4.2 and 4.4 etc right the way up to 5.8. Applying database updates, checking for plugin updates and testing for problems/errors after each update.
Yes, it’s long winded. But we deliver working websites at the end of the process. 🙂
Questions
How to update WordPress 3.5.1?
To update WordPress 3.5.1 audit and update your plugins and theme, then apply WordPress updates step by step. We recommend only skipping one major version, so install 3.7 next, then 3.9 etc.
Getting a WordPress update checksum error?
If you’re getting the WordPress update checksum error the most common cause is a lack of disk space on your server. So clear out old error logs, zips, unecessary backups etc and try again. You can also try manually installing by download the zip file, extracting and copying the files over.
Getting a WordPress update critical error?
To fix the WordPress critical update error is rarely easy – this is why we work on a copy of the site and not the live site. This message displays in your web browser after applying an update as “There has been a critical error on your website. Please check your site admin email inbox for instructions.”
Obviously do check the email as it may reveal more useful information. It’s commonly a plugin or theme that is no longer compatible (look for a filepath in the error message – does it refer to a file for a specific plugin or the theme?). Disabling the offending plugin can get the site functioning again. Or you may need to check your php error log or enable debug mode in WordPress to get to the bottom of this problem.
Can you do this for me?
Yes. 🙂 This can all be fairly complex and painful to do, so we do provide a service to update old WordPress versions. It is important to get this sorted out though as whilst your site may function right now, it’s really living on borrowed time if you’re still running old php versions or WordPress versions as old as version 3.