View Single Post
Old 21st November 2018, 06:15 PM
Leander's Avatar
Leander Leander is offline
Community Manager
Join Date: Dec 2009
Gilde: UK forum
Posts: 5,696

I don't know if the design will change.
Upgrading both buildings requires a fully upgraded Fortress or Underworld. If one of the buildings (e.g. Mages' Tower) hasn't been maxed out yet, you cannot upgrade the Gem Mine to levels 21-25.

Shakes & Fidget Community Manager

Like and follow us on Facebook, Twitter and Instagram
The Following User Says Thank You to Leander For This Useful Post:
Apollo (21st November 2018)