Model changes to carryover over time.
We are currently on .net 4.6.2, which hasn't changed from Source 4.7. We are planning on moving to C# 7, Visual Studio 2019 and .NET 4.8.0 soon, so you will need to make sure you have updated Visual Studio to continue developing plugins in the beta versions. We also intend to move to .NET 5 in 2020, with .NET 5 which will enable the Source command line and service interface to run on Linux.
Results and Configuration Changes
Some results have changed between Source 4.5 7 and Source 4.79. Result changes are mostly around XXXXXXXXXXX. The Annual Accounting, Weirs and specific ordering settings. The eWater development team maintains a detailed system to track when results vary between different version of Source. The details at the following link will help you work out why the results have changed, and any alterations you may need to make to your model configuration. Details of result changes: 4.9 Result Changes from 4.7