How come Kuipers hasn't come off the list?
There's no longer an upper age limit. Previously Kuipers would have come off 12 months ago I think as he turned 45 in March 2018 but now he's fine to continue to the Euros at least.
If there's no age limit why did Rocchi come off?
It's not an automatic extension beyond 45. You have to be nominated by your federation for a +1 year & as well as passing the fitness test also take some other medical tests. He may well have decided he didn't want to carry on for an extra year.
See Vlad's explanation - he talks more sense than me!