Following many comments, we have changed the way player blocking works.
Now blocked players can continue to chat in negotiation threads. They will only be prevented from participating if all recipients have blocked them. Blockages by abuse will therefore have little negative impact. On the other hand, as before, the one who blocks will always be protected from harmful messages because they will not be notified or displayed.
For nominal operation, you simply need to update to version V2.12.4