Dormió o durmió

Dormió o durmió
 

The conjugation for dormir here:

http://www.tomisimo.org/conjugate/dormir

It says that the pretérito for el/ella/usted is dormió. But a class I was listening to says it is durmió. And another site also says durmió:

https://www.spanishdict.com/conjugate/dormir

Is there a difference between these two versions?

Thanks!

Thank you for your sharp eyes!

The conjugation presented by http://www.tomisimo.org/conjugate/dormir is incorrect. The conjugation presented by https://www.spanishdict.com/conjugate/dormir is correct.

I expect that the owner/webmaster of this site will encounter this thread eventually, and he should be able to correct this.

Thanks wrholt!