I found old RB433 device which worked for years as simple NAT box (no reboot or wharever and yet worked very well, so thank you Mikrotik!)
It has ROS 4.5 installed and it says it upgardable to 5.x only. I know 5.x branch won’t under upgrade for years (and for reason) so I think I need to find a way to allow it to be upgraded to 6.x.
Just wanted to ask the procedure for the case. The box is for play only.
Which RB433? In these cases the best option is to netinstall.
The question was how can I make a license “longer”, that is, my RB433 says it’ll permit me to upgrade to ROS 5.x only, but I’d like to up it to fresh 4.xx (mainly for security purposes).
Basically, you have to do it in two steps.
Upgrade it first to 5.26 and then you should be able to upgrade to latest 6.xx version.
Regards,
M.
But what to do with license restrictions? If I upgrade to latest 5.x (5.26) then will the license upgrade limit be moved to 7.x (just like I can see on say some of my 951)?
I wouldn’t worry yet about that unicorn called ROS 7 
In one of the latest ROS v6.41rc50 on RB433AH there is no license restriction limit in upgrade-to-version at all.
Capture-lic.PNG
So, really there is no reason to avoid upgrade to the latest stable version.
Regards,
M.
Email support and ask. They can give you a definite answer or live on the edge and just upgrade
I asked here since: 1) some other people may know that or may want to read that in the future and 2) hope MT persons visit this forum once in a while and my answer. support never replied me before when I emailed them so all my hopes on forum
And yes I did the upgrade to 5.x and then to 6.x, and no problem so far. So thank MT!
Licenses are no longer limited by time. Just Netinstall the unit and the license should become infinite. If not, email support and we will fix it.
Thank you! Actually as I did the upgrade to 5.xx and then to 6.xx and then to 6-stable the device shown me no problems with license so that’s great news!