Alex,
Do you mean in terms of being able to compile the project or searching for interfaces?
I've built it with 10.2.3 Tokyo. I use extensively regular expressions which were introduced in either 2010 or XE (can't quite remember), so those would be the earliest versions of RAD Studio you could compile with (but there is a binary on my website).
As for searching you can search any version of the ToolsAPI.pas file.
D