It's hard to describe a complex program with one word but I would argue they are at least more informative than "modern". Unless you're intentionally using old

It's hard to describe a complex program with one word but I would argue they are at least more informative than "modern". Unless you're intentionally using old technology or going for a "retro-style", pretty much anything written in 2020 could be described as "modern". The alternatives listed as just examples, I would need to understand the program better to come up with a truly apt adjective.