As mentioned many times before in this thread.  This is not an issue with Byteball or the Byteball client.  The issue is that currently there is no standard for signing messages with SegWit addresses.  This is a Bitcoin standards issue, not a Byteball issue.  Someone needs to propose a standard and then everyone would need to adopt and use it.  I am sure as soon as a standard is created Byteball will use it.

Move your coins to a standard address some time before the next distribution (in March) so you can sign a message.