You can now provide a coerce function when defining a prop - every time the prop is updated from the parent, it will be passed through the coerce function. You can think of it as a one-way filter for props, but defined in the child component.

  export default {
    props: {
      msg: {
        type: String,
        coerce: function (val) {
          return val + '' // cast potential values to a string
        }
      }
    }
  }

Fixed

#2001 fix IE9 class merging with both class and :class during transclusion
#2015 handle 0 properly when using v-bind for input value
#2017 prevent v-model syncing value on blur after fragment is removed
#2021 improve template parser when parsing plain strings containing HTML entities
#2022 fix v-show stuck when it is compiled on out-of-dom element
#2023 avoid v-model attempting to sync value after debounce when it is already unbound
#2026 fix v-pre error when used on component root node
#2028 avoid debounce on blur for v-model
#2035 fix SVG class interpolation regression
#2036 non-deep watchers now fire properly when an object's structure has been changed by Vue.set or Vue.delete.
#2042 fix v-bind when binding muted attribute on <video> elements