Older Android versions enabled sharing of the main app directory between Locus Map 4 and Locus Map Classic (former Pro). This is no longer possible due to the recent changes in the Android file system - each app can use only its own private folder.

• Install and initialize the update of one of the Locuses
• Accept the offer to change its main directory:
  
• The app detects the other one and warns of the possible loss of access to the data of the other app after the transfer
  
• Select one of the available private folders into which the data will be transferred
• After the transfer, restart the updated app

It is left without the original data but you can copy the data from the updated app back.

• Update the second app
• Open Settings > Miscellaneous > Default directories > Load Locus Map (Pro) data
• Select and confirm the app directory which content will be copied
• Select Copy from the two options