With the release of iOS 13, Apple has changed the internal mechanism of push notifications. This led to the reset of Kerio Connect account settings on iOS devices. This article walks you through on how to re-enable push notifications on iOS 13.
On your iOS device, open Settings > scroll-down to Mail.
Tap Notifications > select your Kerio Connect account.
Enable Allow notifications and choose the alert type you wish to use: Lock screen, Notification Center, or Banners.
Push notification should appear when you receive emails.