I could get the old sniffer to do almost anything, but the sniffer in 5.8 is totally different.
There is no way to unspecify a port selection. "set filter=port=0-65535" is an error. "set filter-port=default" is an error. "set filter-port=" leaves it set as currently set. The Mikrotik Wiki description doesn't match this at all.
There is no way to specifiy both a src-ip-address and a dst-ip-address to concentrate on a single connection.
There is no way to specify a src-ip-address and a dst-port.
Maybe we could at least get the WIki to describe the feature-set of the new sniffer and describe what's there and what it means. For example, you can give 2 or more filter-ip-addresses. What does that imply? Any of them must appear somewhere in the packet? All of them must appear somewhere in the packet?