Microsoft .NET Version Requirements to Run OnePager Version 5.3
From OnePager Documentation
1) OnePager Pro or Express Version 5.3 requires that the user have installed on his/her computer Microsoft .NET Version 3.5 or later.
2) As a convenience, OnePager will display both the required Microsoft .NET Version and the Microsoft .NET Version installed on the your computer at the “About” tab on the OnePager ribbon’s “File” tab as shown below:
(0.2.1.14-53)