C# version and string interpolation

Hi

When I try to use the $ string interpolation, such as the example below, I get an "Unexpected character: $" error message and the code fails to compile.

double percentProfit = Math.Round(netProfit / Account.Balance * 100, 2);
string percentProfitText = $"Open Position Profit: {percentProfit}%";

This feature was added in C#6 and according to my VS2019, this project, which I created in cTrader and edited in VS, is using 7.2.

I'd prefer not to use the String.Format() method for readability.

Any idea how to get the $ interpolation working?