The `Halogen.HTML.Element.input` function only allows a `min` property of type `Number`: ```hs type HTMLinput = Interactive ( ... , max :: Number , min :: Number ... ) ``` However, for inputs with `type=month`, `min` and `max` take the form of a string with format `YYYY-MM`: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/input/month#min The same issue applies to other input types, listed here: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Attributes/min#syntax