Dismiss the Update Notification?

Hello Sony users!
I updated to Android Marshmallow some weeks ago. Managed to root it and install XPosed.
A week ago i got a notification that theres a new update available but of course i cant install that one.
Now my problem: I cant dismiss that notification. Theres this fancy new "notification manager" but theres not way to disable notifications for the "Softwareupdate-app".
Somebody can tell me what to do please?