As described in the linked issue, there is currently no way to opt out from a deprecation triggered by a validator when using the component standalone.

The example at hand presently is "The "loose" mode is deprecated. The default mode will be changed to "html5" in 7.0" as triggered by EmailValidator. There could be others in the future.

This PR provides a way around:

$builder = Validation::createValidatorBuilder()
	->setConstraintValidatorFactory(new ConstraintValidatorFactory([EmailValidator::class => new EmailValidator(Email::VALIDATION_MODE_HTML5)]));

That's a bit verbose, but that does the job in a future-proof way.