Due to the recent changes in the Android file system, apps can no longer share one data directory. It is possible to transfer the data from one Locus to the other though:

• open Locus Map 4 settings > Backup & filesystem > App data transfer > Load Locus Map Classic data

Both apps share the same data directory but each has different settings. So please do the following:

• install Locus Map 4 to the same storage as your Locus Map Classic (don't worry about any conflict)
• make a complete backup of Locus Map Classic data
• open the backup file in Locus Map 4 backup manager
• restore all items except the points/tracks/routes database (no need to do it):
  
• restart Locus Map 4
• (uninstall Locus Map Classic if you don't need it any longer)