Update: vouchers should work now. Please check that you have the latest app version.. https://www.tier.app/questions-please
[sunday 7. April 2019] : “As we are currently rolling out our new app we have put our vouchers on hold for a short time. We will be back very soon!”
Tip: you can dl older android app version here(voucher codes will work with this) tier.app_2019-04-03.apk
Tip2: You can use this link to login to your Tier account. Add voucher codes, see your history etc…
https://tier.frontend.fleetbird.eu
TIER Electric City Scooters 