[j-nsp] Old JunOS upgrade path

[Ola Thoresen]

My point is only that they made a _lot_ of changes to the underlaying 
systems between 12/13/14 and 15 (as far as I understand it 15 is 
basically forked from 12, so changes done in 13 and 14 are not 
necessarily in 15).  But they still changed a lot, especially the whole 
change from running as a os directly on the hw, to a virtualised 
environment on many platforms etc. started in 15.

So that is why I would suggest going from whatever you have that is less 
than 15, to 15.1, and then going from there to whatever you want to go 
to that is higher than 15.

These days, the major number is only representing the year (it always 
has, but today to an even greater extent).  So the difference beween eg. 
17.4 and 18.1 is not neccesarily  more greater than the difference 
between 17.3 and 17.4.


/Ola (T)