Welcome to Mobiflight.
Nice to have another Real Pilot of an Airliner in our Group!
I not use the 5.3 ( i´m still on 4.5 and FS2020 )
Basically its no factor.... Cause Mobiflight NOT talk to the Sim.... For P3D it talk to FSUIPC!
Correct FSUIPC Version is 6.x ( for P3D v4/5)
The more important Question is..... Will your A320 AddON is Compatible to FSUIPC !
If it not its data to FSUIPC we are also not be able to Read or Write it.
For INPUT most of the things can be done mostly.... But for Ouputs.... There must be a posible way to use FSUIPC from the AddOn Side !
LAST NOTE: Join our DISCORD .... https://discord.gg/99vHbK7
There we can talk for free via VoIP. Also a lot of High Advanced Airbus CP Builders are there and can guide you through the first Steps and know about the AddOns.
I not know all the Airbus AddOns ( I use Boeing only) .... E.g. "Aerosoft" is problematic and need lots of own coding to make it compatible.
"Jeehell FMGS" is much more compatible.... Also Project Magenta is. For FSLBus i don´t know!