Community Moderators ensure that conversations are friendly, factual, and on-topic. We're here to answer questions, escalate bugs, and make sure your voice is heard by the larger Fitbit team. Learn more
It's great to see you around the Community @Robertjohnmckee, hope you're doing great today! 
Would you mind to give me more details about your post? Are you trying to link your Fitbit or MobileTrack to your new phone? What's the model of your new phone?
For the latest list of devices that support the MobileTrack feature, visit the list of our supported devices. Fitbit frequently adds support for new devices, so if yours isn't listed check back soon. Note that we don't provide support for the MobileTrack feature on HTC One M8 mobile devices.
o get started, download the Fitbit app from the Apple App Store, Google Play Store, or Windows Store, and tap Join Fitbit. When asked which tracker you're setting up, choose "No Fitbit Yet?" and follow the MobileTrack instructions.
If you already have a Fitbit account, log into the app and go to the Account screen. Choose the option for setting up a new device and follow the MobileTrack instructions.
Assuming your phone is frequently connected to the internet, your phone always stores data for the last seven days (including today). If you do not have an internet connection for weeks or even months, your phone will store your data until you connect to the internet and sync your data.
On the other hand, if you're trying to link your Fitbit to your phone please let me know the model so I can provide you with the right steps.
Catch you later!
Best Answer