HSL replaces the green travel cards with new blue HSL-cards. At the moment you can replace your travel card at HSL’s service points and other sales points such as R-kioski or grocery stores. You can replace your card for free before HSL implements the new zone model in spring 2019. The card will be replaced automatically if you top up your card at a service point.
NB! If you don’t top up your card from anywhere except ticket machines, you will have to go to a service point to replace your card by the 7th of January, since after that ticket machines will no longer top up the old green travel cards.
This post is also available in Suomi.