I have a server running RouterOS x86 and is on 2.9.39.
All I can find on Mikrotik website is 2.9.51.
Can I go directly to 2.9.51 from 2.9.39 for x86.
I also have 2.9.44 for 100 series.
Will this work for x86?
2.9.51 is the most stable in the 2.9 series, it is recommended that you go from .39 to .51.
I know for 500 Series boards though you could not go directly from .39 to .51. You had to go to .4, then to .5.
This is not the case for x86?
you can go directly up to .51 on any platform. There was the license change with 2.9.18 that might have stopped you, but if your at .39 you can go directly to .51 without problems (on any platform in my opinion). just make a backup of your config first (as you always should before an upgrade).