...and?
I see an array of arrays. The first and second arrays have two strings each, the last one has a float and a string. All those types are concrete.
Let's say those "1.1" and 7.4 values are supposed to be version strings. If your code is only sometimes putting quotes around the version string, the bug is in your code. You're outputting a float sometimes, but a string in others. Fix your shit. It's not your serialization format that's the problem.
If you have "7.4" as a string, and your serialization library is saying "Huh, that looks like a float, I'm going to make it a float", then get a new library, because it has a bug.