How to disable data roaming notification?

Is there a way to disable data roaming notifications? I get them every few minutes when I'm working abroad. And it happens on every acceptable roaming setting (off/national), international roaming setting is no option.

Also, long press > app info (phone app) > uncheck 'show notifications' doesn't solve anything.

Android: 4.4.4 Phones: Sony Xperia Z1 compact and Z3 compact (but was also a problem on my previous phone on Andoird 4.1)