Magento 2.4.8 is the newest release, and together with PHP 8.4 it promises better security, faster performance, and more stability. But for many teams, the upgrade isn’t completely painless. In fact, there are several typical issues that developers have already faced — and knowing about them upfront can save both time and stress.
Here are the most common pitfalls during the upgrade, explained in simple terms.
1. Old code that no longer plays well with PHP 8.4
Magento has a lot of code that was originally written for earlier versions of PHP. After moving to PHP 8.4, some of this code suddenly starts throwing warnings.
The main culprit is how optional parameters are written inside Magento’s internal “building blocks” (constructors). What this means in practice: if your store uses custom modules, they might need small fixes before they run properly.
👉 Tip: Developers can scan custom code to find and fix these outdated patterns quickly, instead of discovering them only after something breaks.
2. Empty style variables breaking the frontend
Another problem pops up on the design side. Magento themes often rely on a set of style variables (like fonts, colors, margins). In older versions, it was technically allowed to leave some of those values blank.
With the upgrade, Magento no longer accepts “empty” style settings. For example, leaving the font setting for a slider undefined can stop the entire frontend from compiling, leading to errors during content deployment.
👉 Tip: Make sure all design variables in your theme have values. Even if you don’t plan to use a specific option, it’s safer to give it a fallback (like a default font or color) instead of leaving it empty.
3. Missing Magento commands after upgrade
In some cases, teams noticed that after the upgrade, Magento’s usual terminal commands (like the ones used to recompile code or deploy content) suddenly disappeared. Without them, it looks like Magento is “broken”.
The good news: this usually isn’t a deep system bug. It often comes from outdated files or an incomplete installation. A quick refresh of Magento’s dependencies usually brings the commands back.
👉 Tip: If your development team sees missing commands, the fix is normally to reinstall dependencies and re-run the upgrade sequence.
4. JavaScript changes that break custom features
Behind the scenes, Magento 2.4.8 has swapped one of its libraries for a newer tool called Uppy (it handles file uploads, for example when you add product images). While this is more modern and reliable, it can break older custom features that were built on the previous library.
👉 Tip: If your store has custom file upload logic or image handling features, budget some time for developers to adapt them to the new library.
5. Caching issues in headless / PWA stores
Stores that use a PWA frontend or rely heavily on GraphQL (Magento’s API layer) can run into caching quirks. Filters or product updates may not show up right away because old data is cached too aggressively.
👉 Tip: If you’re using a PWA or a custom frontend, expect some cache-related fine-tuning. Adjusting cache lifetimes or clearing cached data more frequently usually solves the problem.
6. Extensions that aren’t ready yet
This one won’t surprise anyone working with Magento: third-party extensions are often the biggest risk factor during upgrades. If an extension hasn’t been updated by its vendor, it can cause serious issues — from broken checkout to inaccessible admin pages.
👉 Tip: Always test extensions in a staging environment before upgrading your live store. And if a module is no longer actively supported by its developer, consider replacing it with a modern alternative.
Final thoughts
Upgrading Magento is always a mix of benefits and challenges. Magento 2.4.8 with PHP 8.4 is a big step forward, but it does require some preparation. The main risks come from outdated code, stricter style requirements, hidden dependencies, and third-party modules.
The best approach?
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Run the upgrade in a staging environment first.
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Check your themes and extensions carefully.
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Plan for a bit of extra developer time to iron out these known issues.
Handled correctly, the upgrade will not only improve security but also give your store a stronger, more future-proof foundation.
