Castle upgrade just guves you ability to gain mithril and a little stats boost 40k atta and defense 30k spy att and defense it dosen't do anything with ev
When I click on castle to upgrade I see this. Attack:0 next lvl 2mil Def:0 next lvl 2mil Spy attack:0 next lvl 1.5mil Spy def:0 next lvl 2mil What does this mean?
As soon as you can, you should upgrade your castle. It gives a good boost to your stats for the price.
Those are what added to your raw stats. So if your attack power is 20 million at full troops then with the castle upgrade your attack power will be 22 million. You must remember that only you can see your attack/defense true strength in your profile. When another player sees your profile they are viewing only the ally bonus which is only 2% of your true strength.
Before I decided to do my resets I had upgraded the castle. So I could use mithral now except I don't have any lol. One day I might find a war to help me earn some. My next land is 1.2bil so I might wait on castle upgrade for right now.