Update all your vagrant base boxes

vagrant-box-update-all.sh

#!/bin/bash

# Find all boxes which have updates
AVAILABLE_UPDATES=`vagrant box outdated --global | grep outdated | tr -d "*'" | cut -d ' ' -f 2`

if [ ! ${#AVAILABLE_UPDATES[@]} -eq 0 ]; then
  for box in $AVAILABLE_UPDATES ; do

    echo "Found an update for $box"

    # Find all current versions
    VERSIONS=`vagrant box list | grep $box | cut -d ',' -f 2 | tr -d ' )'`

    # Add latest version
    vagrant box add --clean $box
    BOX_UPDATED="TRUE"

    # Remove all old versions
    for version in $VERSIONS ; do
      vagrant box remove $box -f --box-version=$version
    done

  done

  echo "All boxes are now up to date!"

else

  echo "All boxes are already up to date!"

fi

vagrant box outdated --global

Updated version based on what @thom8 did to account for all providers

https://gist.github.com/sc250024/05a5aa1a1ee2db02080f8714226986e9