Are RNG box souls upgradeable?

[Ironpoetry]

Anyone know if the worthy souls/talisman you can buy with the RNG box coins are upgradeable as there are no progression paths listed on the tooltip? 

 

In previous events, you could upgrade souls onto the normal progression path...

[Arohk]

You can't upgrade them, don't bother with buying them, waste of money.

[Cyan]

The Worthy ones are not upgradable. In the article we published yesterday we had this note: "Worthy items cannot be upgraded. When a higher tier of Worthy items is released, there will be way to upgrade your existing Worthy items to the new tier."

[Szellodal]

Unfortunately this info was missing from the previous posts. Is there any chance to make it account bound so we not waste all the coins?