TomTom app V1.29 still works perfectly with iOS 15
I still use this app when I know that Traffic info is unlikely to be important as it's so much easier to select the address you want to drive to with the simple:- Town->Street->Number rather than the slow & erratic Search that may or may not find where you want to go & depends on you having a network signal.
For those who still have the app on their iPhones you need to Disable the Offload Unused Apps option because Tomtom have removed the download so if it gets removed you can never get it back. I don't know why Tomtom have removed this download from the App Store. If you paid for the app surely you should still have the option to re-download it forever?