Not sure if this hacker is good or bad. Lets see if on the next step he will upgrade routers or reset their configuration

I did test upgrade from 5.26 to this version. Just for testing. Everything went well. Upgrade failed for you due to configuration or something like thta. In general it works just fine.

I did test upgrade from 5.26 to this version. Just for testing. Everything went well. Upgrade failed for you due to configuration or something like thta. In general it works just fine.

On which version did you have an original problem?
Sounds like the problem which was already resolved a long time ago and recently there was a speciap annoncment from Mikrotik team about that. If I remeber correctly then versions before 6.38.5 were affected.

You just simply decided on a nice Saturday morning to upgrad from 5.xx over more than 43 releases to an rc version and are surprised that it did not work? I am not. You should expect a problem if you upgrad any software between so many releases.

With massive upgrade I did mean many devices at the same time. I have upgraded all of mine as soon as I heard about the problem. But I always perform an upgrade one device by one. I have learned that from release topics where people are complaining that all of the devices have to be reinstalled due ...

Also I would never leave an open access for anyone besides me or other administrators for particular services. Had some of the MIPSLE units running on old version at the clients office - all of them were affected. Fixed them with Netinstall. Problem was - do not trust particular IP addresses. There ...

I would never run a massive upgrade on my network. What if something goes wrong? I think that massive router upgrade is not a very smart idea.

Seems funny that you blame Mikrotik for releasing version on Friday like it would be mandatory to upgrade your core routers now. Ran into some issues after upgrade but that was my mistake. Recommend to read changelog before an upgrade first, got a little bit confused after I upgraded my first router...