please make a feature request - to be able to unset ‘prefix’, as it’s broken at least since v3 
p.s. will 5.7 be released today?..
it is fixed for unset for .routing filter.
and it seems no, there are some problems found that have to be fixed. Some features will be tested more thoroughly (there is something new coming in webfig 
)
hmmm… I thought, I have 2 unanswered tickets just because you will work on them just after today’s v5.7 release 
What’s new in 5.7 (2011-Sep-14 10:54):
*) ovpn client - fixed crash when user name or password together
were longer than 11 symbols;
*) sstp client - added an option to skip
server address verification from certificate;
*) fixed problem - router crashed sometimes when using USB modem;
*) userman - show overall totals, show user totals if user has more
than one entry;
*) lcd - retrieving ‘/system lcd page’ configuration did not work with
hundreds of interfaces;
*) webfig - added ability to reorder fields in skins;
*) webfig - added ability to add/remove new tabs & separators in skins;
*) webfig - added ability to add any field to special status page;
*) webfig - fixed problem when user sometimes got logged out with message
“internal server error”;
*) webfig - logout didn’t log user out from router;
*) webfig - added System/Password for changing user’s own password;
*) system reset-configuration - if keep-users is specified ssh user keys are
preserved as well;
*) ipsec - new exchange mode (main-l2tp) for l2tp tunnel users to allow
FQDN as a peer ID with preshared key authorization in main mode;
*) ssh - fix possible server crash when connection is interrupted;
*) improved ipv4 forwarding performance on all boards with simple configuration
by up to 30%;
*) add passthrough setting to change-dscp, change-ttl, change-mss,
strip-ipv4-options, change-hop-limit mangle targets;
*) ipsec - fixed problem of RB1200 rebooting when large amount of UDP traffic is
sent through IPsec;
*) sniffer - added more useful packet filtering options, also available as quick
mode command parameters;
The Winbox issues seem to be fixed and also the L7 problems do not show up in the logs anymore (so far). The 30% increase is visible.
Edit: nope, the 0.0.0.0 winbox prefix bug seems to be fixed. The L7 messages in logs are still there.
any details?