Something that MikroTik forgot to write in changelog that is more important than everything else:
If you had set a country and use frequency mode superchannel, updating to 6.43.8 will set regulatory domain.
What does this mean? If you don’t use frequencies in default scanlist, you are going to lose stations.
Set country to no_country_set before upgrading.
P.S. Thank you MikroTik, instead of TDMA REAL improvements or a new Dude, a present that is a pain in the a*s.
Christmas surprise 
…
In my dreams MT sell wireless division to another company …CAMBIUM 
. Don’t troll more please.
Good idea, they don’t have any innovation @5Ghz Outdoor Wireless in the last 4 years…
I’m absolutely serious, try to update and see what happens.
I use country setting with superchannel as a way to set default scan-list and then add licensed frequencies to it (scan-list=default,5940-6100).
country=no_country_set means FCC compliant set of channels, so scan-list may need to be set first to avoid losing connection (if the current channel is not FCC compliant).
One thread about the same, closed.
http://forum.mikrotik.com/t/6-43-8-update-alert-read-before-update/126150/1