Contacts on your device (phone numbers, first and last names) will be seamlessly uploaded to Telegram servers so you could find them in **Contacts** section of **%1$s**, or receive a notification once they join. When you delete a contact on your device while sync is on, it will also be deleted from your contacts list on **Telegram** servers. You can always turn sync off or clear data on Telegram servers via **Settings > Privacy and Security > Delete Synced Contacts**. To turn sync on, you also have to allow **%1$s** to access contacts on your device.