You have a 48 (24 for DIN Time:Hrz) hour trial period after which a popup will display instructions about how to proceed with your purchase. If you do not want to wait with your purchase you can end the trial early in the settings page, almost at the bottom.

Purchases are handled by k·pay, a third-party service.

When the trial ends or you manually end the trial from the settings page this will happen:

1. A popup will appear on your watch with instructions and a five-digit code.
2. Visit kzl.io/dintime or kzl.io/dinhrz and follow the instructions.
3. When payment has been made DIN Time will automatically unlock all features after a minute or so.

There are some extra steps are needed to re-activate your purchase of DIN Time. This is due to a limitation in the Fitbit platform, unfortunately. Fitbit doesn’t provide any unique identifier for each watch/person. So the purchase is linked to your current installation and your email address instead. But to get you back on track do this:

1. Open the DIN Time settings page and scroll all the way down to a section labeled "License status". Flip the switch labeled "End trial now". After a few seconds the popup with a five digit code will appear on your watch.
2. Visit kzl.io/dintime or kzl.io/dinhrz as you did last time and tap or click on “Already purchased” and follow the instructions to reactivate DIN Time.

After 24–48 hours you are required to purchase DIN Time or DIN Time:Hrz to continue to use it. During the trial period all functions are fully functional, but any customised colors on the watch will periodically reset to black and white.

First, the Fitbit app on your phone needs to be able to access the GPS to determine where you are. So make sure you have allowed “location services”.

Also…

…there has been a known problem with the connection between the Fitbit Ionic and the Fitbit app on your phone. There is a part of DIN Time running on your phone that is responsible for downloading new weather data. It is called the “companion app”. If the connection between phone and Ionic is lost the app shuts down and stops updating the weather. You can try exiting DIN Time on your watch and start any other app, for example Alarms or Weather. Stay there for a few seconds, then return to DIN Time. Hopefully the companion app gets relaunched and the weather will start updating. If this doesn’t help repeat the procedure but also force quit the Fitbit app on your phone before relaunching DIN Time on your watch.

You are most likely trying out DIN Time or DIN Time:Hrz in trial mode. Colors will reset to black and white every 30 minutes in DIN Time:Hrz and every 2 hours in DIN Time.

No.

Yes, Deutsches Institut für Normung. It’s the German Standards Institute. They developed the typeface DIN Time is based upon. The typeface was used for road and highway signage. The design of DIN Time was also originally inspired by these highway signs, but more so on the Pebble. Some elements has been removed for the Fitbit version. You can still see traces though, like the naming of one of the themes, Autobahn. The dashed line around the forecast is another thing. On highway signs a dashed box around a road number shows that the current road or exit leads to that road, ie. what’s coming -> forecast. Pretty far fetched, but I like it.