interestingly when I clicked version history it crashed the app
but from the report It looks like I'm running v6.3 on with IOS 10.9.5
Process: iReal Pro [10276]
Path: /Applications/iReal Pro.app/Contents/MacOS/iReal Pro
Identifier: com.massimobiolcati.irealbookmac
Version: 6.3 (8980)
App Item ID: 409035833
App External ID: 812767055
Code Type: X86-64 (Native)
Parent Process: launchd [509]
Responsible: iReal Pro [10276]
User ID: 501

Date/Time: 2019-03-28 13:20:14.042 -0700
OS Version: Mac OS X 10.9.5 (13F1911)
Report Version: 11
Anonymous UUID: 5FD5AC07-6A6C-514F-C62C-C0508E905D1A

Sleep/Wake UUID: 58A70572-7C83-48C9-AA34-751F7612B9E7

Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Exception Type: EXC_CRASH (SIGABRT)