The actual client version will be redesigned, will have a new login screen and a launcher that allows you to install and update the stand-alone client more conveniently.
The technical side of the client will be completely revamped to make Tibia fit for the future.
A group of randomly selected players can try out the new client version, those who have been selected received an email invitation on their registered Tibia email address with further instructions.
The test will be open to everyone eventually, so everyone will get the chance to experience and test the new client version before its official release.
Take in mind this is NOT like a test server; you will log in and play on your regular game world but with the Beta version! Any damage your character takes, death or experience in-game will count as a normal gameplay.