Is browser support good enough?
https://caniuse.com/#search=datetime-local

Anyway, isn't it a BC break? JS apps may rely ontype="datetime". Not sure it is worth it.

type="datetime" is supported by exactly 0 browser out there, meaning checking the type DOM property gives youtext due to the type fallback.
And thedatetime type is removed from the HTML spec.

However, the HTML5_FORMAT constant has the timezone included in the format. So it should be updated fordatetime-local to remove the timezone part.

Is this enough? I mean is the format in which data is sent by browsers the same as it was meant to with the olddatetime type?

From my short test, it seems Chrome submits thedatetime-local without a timezone. So@stof would be right that\Symfony\Component\Form\Extension\Core\Type\DateTimeType::HTML5_FORMAT needs to be changed.

Would it not be considered a BC break to change the value of a constant?

What's the status of this? Can I help?

@pierredup let's do the change as requested by@Tobion /@stof

@Tobion aren't we ready here?

Thank you@pierredup.