Help with SCADA using modicon PLC

[hazwer]

I am working with an automation consultant and I am given a project to design SCADA for our client. At present there are 20 RTUs with E984-258. We are planning to replace 5 RTUs with 140CPU43412A and leaving 15 RTUs with same controller (E984-258). The MTU is being replaced with 140CPU47160 (with hot standby). All RTUs are communicating via wireless, and using inTouch 10.1 as SCADA software.
Now problem is that previous RTUs support MODSOFT and the MTU we are replacing only support UNITY Pro 2.0. Will this design work or should we replace MTU with the one that supports MODSOFT but we want hot standby option? Please help me.

 

[chud]

Modsoft, is an obsolete software. Unity pro v8 is the latest software used with the quantum range cpu's.

 

[hazwer]

Thanks for the reply.
I know but the remaing RTUs are using and only support Modsoft so is there any possibility that I can communicate 140CPU67160 (MTU) which does not support Modsoft with the old RTUs (E984-258)?