We have been testing the latest release candidate version of SQL Server 2016 with Forecaster 7.0, SP5.
To date, there have been no problems with Forecaster itself. No unexpected errors, no connectivity issues, no functionality failures. The database wizard has worked properly so far but has the requirements described in the articles linked below. If you need it, you should test the database wizard out to make sure the prerequisites are installed. There are many workarounds if your environment has trouble with connecting the Database Wizard to SQL Server 2016 - contact us and we can help you out with this.
Note that connecting to SQL Server 2016 will still require that you follow the instructions for connecting to SQL Server 2008 and higher databases. Details of that are here:
Bottom line: Forecaster 7 appears to work absolutely fine with SQL Server 2016. This is good news! I will update this post if new information comes to light about it.