Hi there!
Thank you for bringing this to our attention and sharing the details of your debugging process. I understand how important it is for your discount code logic to work consistently, especially when relying on custom code that checks coupon codes.
Regarding your question, Coupons are not case-sensitive like we mention here https://woocommerce.com/document/coupon-management/#adding-a-coupon
Also, I reviewed our changelogs and documentation, and there hasn’t been an official announcement about changing case sensitivity in coupon codes, so this may be more related to how your custom code interacts with WooCommerce’s API or a subtle internal change.
To ensure your code is robust and not dependent on case, I recommend normalizing the coupon code string by converting both sides of your comparison to lowercase (or uppercase). For example:
if ( strtolower( $coupon->get_code() ) === 'abcdef' )
Thank you
Well, i just checked my old staging site running on woocommerce 9.8.5 and there the discount code overview table displays all codes with lowercase and in editor with uppercase as that is the way i always is typing their name. And with version 9.8.5 i can use the below code:
if ( strtolower( $coupon->get_code() ) === 'abcdef' )
Then when i updated my staging site to WC version 9.9.4 the discount code overview table displays all codes with uppercase (as i have typed them) unless if i have save it using lowercase, then it also appear in overview table in lowercase.
So the 9.9.4 version now saves the coupon code as you type it and not as lowercase in which it did in version ie. 9.8.5.
A little more tricky when using codes as below:
WC()->cart->has_discount( 'xxxx' )
WC()->cart->apply_coupon( 'xxxx' )
WC()->cart->remove_coupon( 'xxxx' )
As we need to use case-sensitive comparison for them to work with both uppercase and lowercase discount codes. And as you said this behaviour is not mentioned in any changelogs.
Brgds
Rune
Hi there!
Thank you again for the detailed follow-up — it really helps!
I’ve tried to replicate the issue on my test site, and indeed, I’m able to see the same behavior you described.
- In WooCommerce 9.8.5, coupon codes are saved and displayed in lowercase, even if you type them in uppercase.
- In the latest version, coupon codes now appear exactly as typed — so if you enter a mix of uppercase and lowercase, that’s how they’re saved and shown in the overview table.
Also, I’ve looked into this and found that our developers are already working on making coupon code checks case-insensitive, as mentioned here:
👉 https://github.com/woocommerce/woocommerce/pull/58918
Hopefully, this will be resolved soon in an upcoming update.
Hi @metuza,
Thanks for the detailed follow-up, Rune. I really appreciate you digging into the version differences; your insight here is super helpful.
You’re absolutely right, starting with WooCommerce 9.9.4, there’s been a subtle but impactful shift in how coupon codes are handled. In previous versions like 9.8.5, coupon codes were automatically normalized to lowercase behind the scenes. But in 9.9.4, WooCommerce now appears to preserve the exact case used when a code is entered, which also affects how methods like WC()->cart->has_discount(), apply_coupon(), and remove_coupon() work, effectively making them case-sensitive.
I ran a quick test on my own staging site, and I’m seeing similar behavior. Existing coupons are now displayed in uppercase, and newly auto-generated codes are also uppercase by default. However, when I manually enter a coupon code in lowercase and save it, it still saves and functions correctly, so lowercase codes do still work if entered and used consistently.
Since this behavior change hasn’t been documented in the changelogs, I’ll raise this internally so we can confirm whether it’s an intentional update or a regression and ensure the documentation gets updated accordingly.
In the meantime, if you prefer lowercase coupon codes, you can manually edit and save them as such. Just be sure your usage in code matches the exact case, or normalize the comparison using something like strtolower() to ensure compatibility across all methods.
Let us know if anything else comes up!
Hi @metuza,
Just following up to let you know that this behavior has been confirmed as a regression and is actively being addressed. The WooCommerce team is working on restoring case-insensitive handling of coupon codes, and you can track the progress here: https://github.com/woocommerce/woocommerce/pull/58918
Once merged, this should bring back the expected behavior where coupon codes work regardless of letter casing, both in admin logic and during cart interactions.
I appreciate you bringing this to light; your detailed observations really helped! Let us know if there’s anything else you notice or need help with in the meantime.
@metuza nice job on the investigation – one of the big sites we handle has been dealing with this problem. It caused a ton of issues. We added a front end hack to send this to lowercase, without deeply understanding this issue. Your explanation helps us realize this wasn’t a conflicting plugins, misconfiguration, or anything besides a mistake on the end of WooCommerce.
Thanks @lovingbro for addressing it quickly on your end. This stuff happens, and it’s important it’s handled well, which I think you guys did.
Hi @brianstinar,
Thank you for your kind words and for taking the time to jump in here — I’m really glad Rune’s detailed investigation was helpful to your team as well!
Just to update you further, the fix for this case sensitivity regression has already been merged into WooCommerce’s codebase a few hours ago. You can continue following the progress on the original pull request here: https://github.com/woocommerce/woocommerce/pull/58918
The fix will be included in the next WooCommerce release, so feel free to keep an eye on our changelog page for the official release notes and schedule: https://developer.woocommerce.com/changelog/
Thanks again for your feedback and support — if you’ve found this helpful, we’d really appreciate it if you could leave us a ⭐⭐⭐⭐⭐ review here: https://ww.wp.xz.cn/support/plugin/woocommerce/reviews/
It goes a long way in helping us continue to improve WooCommerce for everyone!
