Old versions of "split" don't have the option "--additional-suffix", which makes VeChat terminate with an error. I don't know in which version this option was introduced, but it was definitely absent in 8.4, but present in 8.30. Maybe, it's worth to indicate the minimum version of "split" in the "Installation and dependencies" paragraph, or to change the source code of VeChat to make it work with older versions of "split".