Why does this convert to lowercase?

[9mm]

I just lost so much time because it seems either this library, or my partners php base62 library is behaving very unexpectedly.

This one converts 10008287 to fzbz and his converts it to FZBZ.

I checked another base62 gem for sanity... this one: https://github.com/steventen/base62-rb

And it also does it as FZBZ. Every other library I've tried thus far uses uppercase.

Do you know why this is? I thought there was only 1 kind of base62, without any room for variation?

[ysllyfe]

@9mm the PRIMITIVES key sequence in this gem is 0-9 A-Z a-z, base62-rb is 0-9 a-z A-Z, you can choose or modify it yourself
Still not yet a standard CharacterSet for the Base62.
But the "A" ASCII is less than "a", so i think 0-9 A-Z a-z is more Suitable