If I may, I see a lot of ICOs now promoting pre-sale with some amount of coins locked in. So they might say - 20% of the coins are held for development team. Out of this, 5% (or 25% of the developer coins) are released each year.
Any ideas on how this is implemented?
And is there a way to change supply later?
This logic can be coded into the original contract with a timeout. According to the contract each year a certain percentage of the token will be transferred to the developers’ addresses.
That can still be in the original contract to transfer 5% of tokens to dev team adress each year. But you can update the contract by spending eth to change it AFAIK.