In regards to RouterOS upgrades, RouterOS can be Licensed with two types of keys, L3/L4, and also L5/L6
The difference between these is that L3 and L4 only allow RouterOS upgrades until the last update of the next version. L5 and L6 however, give you the ability to use one more major version
There are also differences between all License levels (L3-L6) that are unrelated to RouterOS upgrades, see License levels
So the math is:
L3/4 = current version + 1 = can use
L5/6 = current version + 2 = can use
eg. L5/6 = v3 + 2 = v5.21 you can use
Examples:
If current version is ROS v3, L3 and L4 will work with v3.1, v3.20, v4,1, v4.20 but NOT v5.0 and beyond
If current version is ROS v3, L5 and L6 will work with v3.1, v3.20, v4.1, v4.20 and also v5beta1 but NOT v6.0 and beyond
If current version would be ROS v4, L5 and L6 will work with v4.1, v4.20, v5.1, v5.20 and also v6beta to v6.99 but NOT v7
Change license Level
There are no license level upgrades, if you wish to use a different license Level, please purchase the appropriate level. Be very careful when purchasing for the first time, choose the correct option.
Why is it not possible to change license level (ie. upgrade license)? Just like you can’t easily upgrade your car’s engine from 2L to 4L just by paying the difference, you can’t switch license levels as easily. This is a policy used by many software companies, choose wisely when making your purchase! Instead we have lowered the prices, and removed the software update time limit.
So. You better buy new Level6 License. and upgrade to 4.5 for old license. that’s it.
But, You can save money to buy new level 6 license if you buy from http://www.mikrotik-routeros.net/ they sell far cheaper then here.
I can’t really understand why. but my license is working.