Installed it onto my iPhone and all my accounts I had before were all gone…
Why?! 😢 

Also, I loved my custom colours of red and black, how do I get those back? 

 Sorry. Known issue for iOS. Apologize for the inconvenience.

For theme go to Settings > Display 

 and for prior balances? 

 Read this https://docs.zeusln.app/for-users/embedded-node/backup-and-recovery/