Indeed, a few years ago, this was true, but meanwhile, the corresponding guidelines have changed, such that only partial wipes or replacements of particular quests, stats or items are to be expected as needed, but other player data will be widely conserved. For details, see the source topic:
This question has been asked plenty of times, and the answer is the following.
We will do our best to preserve the characters we have in game at every upgrade of the game.
[...] overall I want to be sure people understand that their chars will be kept [...]
EDIT: Wow, this quote is already three years old? And I did not mean to make a pseudo-official statement, so thanks for Eonwind's confirmation
