How will you motivate them to upgrade? The decision should have been made to mark a new mandatory version sooner, we had a few important changes (last mandatory was 3 months ago: 3.5.8.8 (released on 2017 April 2))
And ofc when the situation is correct analyzed that the new version really fixes this problem
Anyways, let's try with manually calling out:
It is not a mandatory because old versions still work.
And the superblock problem is not system breaking - even if it is solved in .2
Gridcoin IRC tweeted @ 07 Jul 2017 - 06:12 UTC
Disclaimer: I am just a bot trying to be helpful.