Example of updating an app's provisioning profile expiry time in a Firebase realtime database (gist for https://chris-mash.medium.com/using-provisioningprofile-and-firebase-to-monitor-profile-expiries-remotely-7832f475d7b7)

ProfileExpiryLogger.swift

//
//  Created by Chris Mash on 10/02/2022.
//

import UIKit
import ProvisioningProfile
import FirebaseDatabase

// NOTE: this gist uses some personal extensions I've written which aren't shared here but you should be able to swap out easily enough:
// Bundle.main.appVersion
// Bundle.main.appName
// UIDevice.current.deviceModel

public struct ProfileExpiryLogger {
    
    public static func logProfileExpiry() {
        // Grab the expiry time using https://github.com/ChrisMash/ProvisioningProfile
        guard let expiry = ProvisioningProfile.profile()?.expiryDate else {
            NSLog("ProfileExpiryLogger ERR: Failed to get provisioning profile expiry, not logging anything to Firebase")
            return
        }
        
        // Grab the vendor ID and log all this to the DB
        getIDForVendorAndUpdateDB(with: [
            "version": Bundle.main.appVersion,
            "expiry": expiry.timeIntervalSinceReferenceDate,
            "updated": Date.now.timeIntervalSinceReferenceDate
        ])
    }
    
    // MARK: Private functions
    private static func getIDForVendorAndUpdateDB(with data: [String: Any]) {
        // Grab the vendor ID as a unique (unstable, read up on it if you don't understand why) identifier for the device
        guard let idForVendor = UIDevice.current.identifierForVendor else {
            // NOTE: This can happen prior to, or just after, the device unlocking (after a restart)
            let delay = 2
            print("ProfileExpiryLogger: Failed to get vendor ID, trying again in \(delay)s")
            DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(delay)) {
                getIDForVendorAndUpdateDB(with: data)
            }
            return
        }
        
        // Create a reference for the device using the device model and the vendor ID
        let deviceID = "\(UIDevice.current.deviceModel): \(idForVendor)"
        // Update (or add if it doesn't exist yet) the DB entry for this device
        Database.database(url: "your-database-url").reference()
            .child("devices")
            .child(deviceID)
            .child("apps")
            .child(Bundle.main.appName)
            .setValue(data) { error, dbRef in
                if let error = error {
                    NSLog("ProfileExpiryLogger ERR: Failed to log profile expiry details to Firebase: \(error)")
                } else {
                    NSLog("ProfileExpiryLogger: Successfully logged profile expiry details to Firebase")
                }
            }
    }
    
}