Yes, starting with version Threema 5.1 for iOS, you can choose which information should be included in push notifications for incoming Threema messages. Depending on the option you choose, some information is shared with the operating system (OS).
The following options are available in the Threema app (in “Settings > Notifications”):
Independently of these push-notification settings, you can define whether you want to give the OS access to information about interactions or not, see this FAQ entry.