Hi Magro,
Yes that should be fine...Just make sure that your MDs (controllers) will be running at most 2 older versions as compared to the MM.
For example, MM can be running 8.6.X while MDs can be running 8.4.X or newer...
Later on, when you upgrade your controllers, just check that they are supported on the new version in case you have old APs..
I recommend you check this video as well for a demo for this step.. https://www.youtube.com/watch?v=IoKUrGXpR9g