A custom WordPress plugin nobody maintains isn’t ready for PHP 8: what now?
Short answer
No update will ever fix custom code, so someone has to change it. First find exactly what breaks on the PHP version you need: the free CompatNav plugin lists each problem with the file, the line and a before/after example. Then decide: fix, replace, or remove. For the fix, CompatNav Pro (launching 31 October 2026) prepares the exact code changes as patch files for 14 kinds of findings, each checked before you see it. Nothing is applied automatically: a developer reviews and applies them.
Why custom code is the real risk
Plugins from wordpress.org and maintained premium plugins get updates: when PHP changes, their developers usually ship a fix, and you install it. A plugin written for your site years ago gets nothing. The day the host moves the site to a newer PHP version, it stops, often with a fatal error, and with it every page that uses it.
The usual causes in old code are the ones PHP 8.0 removed (php.net): create_function(), each(), curly-brace offsets, nested ? : without brackets.
Step 1: find exactly what breaks
The free CompatNav plugin checks every plugin and theme for the PHP version you choose. For each one it shows whether an update is available and whether the code looks like your own, and for each problem, the file, the line, a plain explanation and a before/after example:
That list is your work order. Often it’s shorter than feared: code already protected by function_exists() or a PHP version check isn’t reported.
Step 2: fix, replace, or remove
For each custom plugin:
- Still needed and small? Fix it. The list says where.
- A maintained plugin does the same? Replace it, and save future work.
- Nobody uses it? Remove it: the cheapest fix there is.
Step 3: get the exact changes, checked
CompatNav Pro, launching on 31 October 2026, goes one step further for code that isn’t from wordpress.org: it prepares the exact changes as patch files for 14 kinds of findings. Before you see a change, it is checked:
- the result is valid PHP on your current and your target version,
- the finding is gone,
- nothing new appears.
Each kind of change was also run before and after on the official PHP builds. Nothing is ever applied: your files stay as they are until a developer reviews the patch and applies it.
Then test and switch
Apply the changes on a staging copy, test the pages that use the plugin, run the check again, and switch the live site. “Was the fix applied?” in Pro checks the changed places again without a full scan.
Key takeaways
- Custom code gets no updates: the only fixes are the ones someone writes.
- Find the exact problems first: file, line, and how to fix each, for the PHP version you need.
- Decide per plugin: fix, replace with a maintained plugin, or remove it.
- CompatNav Pro prepares patch files for 14 kinds of findings, each checked to be valid PHP on both versions.
- Nothing is ever applied automatically: your developer reviews every change.
Frequently asked questions
How do I know a plugin is custom?
It isn’t on wordpress.org and nobody sells it: it was written for your site. CompatNav marks plugins whose code looks like your own, and shows whether an update is available.
Can the fixes be applied automatically?
No, deliberately. CompatNav never changes your files. Pro’s suggestions are patch files for a developer to review and apply.
What if nobody knows how the plugin works?
Then the patch files help most: each change is small, explained and checked. If the plugin isn’t needed any more, removing it is the cheapest fix.
Check your own site before you upgrade
CompatNav is a free WordPress plugin. It reads the code of your plugins and themes on your own server and tells you, in plain words, what will break and what will only show notices on the PHP version you choose. It never changes your code. It can’t see problems that only appear while code runs with real data, so a quick check of your site after the upgrade still matters.
Sources
About the code examples: each output is the real output of the code shown, run with the official PHP builds, without a php.ini, with all errors reported and displayed. Only the file path was replaced by a neutral server path.