[Bug]: Card-mod will break in Home Assistant 2026.8

[dcapslock]

Changes in Home Assistant renaming developer-tools to tools will break card-mod due to yaml theme loading.

UIX fix for this is in beta. See commit - Lint-Free-Technology/uix@3a82a23. This allows both 2026.7 and 2026.8dev to current work with card-mod.

Without any fix, card-mod will break in Home Assistant 2026.8.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[derMicro]

Yes, I can confirm that, the browser was going through hell and was on the verge of crashing. I was forced to roll back to version 2026.7.4 using the backup.

[theRealBassist]

Seconding this issue. Themes that rely on cardmod completely break as well. I also had to roll back to a previous backup.

[dcapslock]

For those experiencing this issue you have the option to migrate to UI eXtension (UIX) - See FAQ for more.

[jeroeneg]

I have the same issue, no CSS is being applied anymore. I do not want to migrate to UI extension. Cause I need to do everything from scratch then. What are the options right now or is this being fixed?

[martinkellerka]

@dcapslock So this means there will be no fix for Card-mod and we have to migrate to UI eXtension with HA 2026.8 ? Or is this just for those who can´t/do not want to wait for a Card-mod fix? If the latter, what is the estimated time frame for a fix?

[dcapslock]

Cause I need to do everything from scratch then

@jeroeneg Check the UIX FAQ linked. Nothing needs to get redone. UIX is a drop in replacement.

@martinkellerka I won't be releasing a fix as I have moved on to UIX more than 6 months ago.

[jeroeneg]

Cause I need to do everything from scratch then

@jeroeneg Check the UIX FAQ linked. Nothing needs to get redone. UIX is a drop in replacement.

@martinkellerka I won't be releasing a fix as I have moved on to UIX more than 6 months ago.

Thanks, moving to this UIX works fine again, happy it got fixed :) I removed Card-mod for now further.

[Mariusthvdb]

As this seems to be the real start of card-mod no longer being in sync with HA and maintenance of card-mod appears to not be very active, I must say I feel a bit sorry really.

Card-mod has been my to go to for many many years (especially after having stopped custom-ui completely) and I hate to see it lose compatibility

Having said that, I guess thats how things evolve in our playground, and really happy to see UIX replacing it and leverage even further

Id like to express my gratitude here explicitly.
Im very grateful to Thomas and what he’s done for my frontend all these years.

Also find it amazing he has a pinned response to the UIX repo showing what a cool guy he really is.

[aureq]

I second what @Mariusthvdb said 👆. I'm really grateful for this very useful project, and for both @dcapslock and @thomasloven to have done an excellent work.

@dcapslock could it be possible to update the README.md and add a deprecation notice along with a link to the UIX repo please? I think that would reduce the amount of issues/questions raised here.

[TRON4R]

Are there any disadvantages with uninstalling card-mod and installing UIX instead?
As far as I understand, UIX supports the exact same syntax, so nothing else would need to be changed, correct?