If you can add switch button on either setting or hero’s page to let players choose the appearance they want, it would solve the problem permanently. Because this won’t be the last time that some heroes’ appearance need to changed to reboot version.
On setting page - graphics
Option button: default look / reboot look
When default look selected, all heroes’s default skin will be active.
heroName_skin_default
heroName_skin_reboot
On hero page, if it’s possible, can even make a button to manually switch specific hero’s appearance. ( see screenshot). The new button only visible when there’s reboot skin available.