Option to convert from version 3.0 to 2.1

[Johann-Tree]

I have not found a command-line tool that can convert from VCard Version 3.0 (or 4.0) to 2.1.
Need this to import contacts to mobile phone (old Android).

[jowave]

This cannot be easily done with my code, so it would be easier and better to write a new tool.

Probably, I do not have time to work on this, but I am open for contributions. It may even be easier, since there are libs which can read VCard 3.x or 4.x. For example PyVCF or vcfpy, but I have not tested them.