According to the official listing on the Apple App Store, is designed for power users and IT professionals:
: Indicates the app is compiled for 64-bit architecture (required for modern iOS devices).
: Connects to Windows, Mac, Linux, and NAS drives using SMB/CIFS.
: Since this is a file manager with "Professional" access, a compromised version could grant attackers access to your private cloud storage and network passwords.
: Likely signifies the minimum system requirement or the SDK it was built for, in this case, iOS 9.3 .