Hi mducharme,
Can you please suggest me some examples???
I don’t know the exact command, but you would need to do an UPDATE query with a LEFT JOIN for the same table twice (the radacct table both times) WHERE the delegatedipv6prefix field is NULL to SET delegatedipv6prefix to the prefix found in the matching accounting entry for DHCPv6 RADIUS accounting (using the MAC address to match in the LEFT JOIN). You may also need to add another custom field to indicate whether this was done successfully, as otherwise this query would needlessly run for IPv4-only sessions and put a higher load on the device if you run it on a scheduled basis.
fasttrack doesn’t seem to work (CHR on ESXi 6.7) VMXNET3
Hi. RB4011iGS+ model here with v7.1rc6 - today I wake up with internet not working. Turns out DNS not working everywhere, even in router (nslookup google.com). Querying manually on PC (nslookup google.com 1.1.1.1) also did not return anything. Like - there is no connectivity at all… But I was able to connect to the router via IP (not via ip>cloud) and perform reboot.
After reboot it’s fixed. Before that router was up for several days/weeks without being touched at all and everything worked great.
It’s a first time Mikrotik device got fixed by rebooting it. 
If this happens again, I will sure raise a ticket to Mikrotik support to get this issue fixed. I did not take supout and therefore not raising any ticket now. 
When it happens again, it is a good idea to look at the DNS window to see what values it has for “cache used” and also open the Cache subpage to see how many items are there.
And of course take a supout file when that still works…
New version 7.1rc7 has been released in development RouterOS channel:
http://forum.mikrotik.com/t/v7-1rc7-development-is-released/153617/1