Netrunner, one of the best card games on the planet, is in for some changes next month after Fantasy Flight announced a revised core set.
The core set itself seems cool! It's a great starting point for new players, since it includes everything you need to get started with the game (Netrunner is an LCG, which means you buy booster packs), only now with new art.
But of more importance to existing players -- those playing competitively especially -- is what else is coming: a "system refresh" (or rotation) on October 1, which will change the eligibility of some of Netrunner's cards.
As of October 1st, the cards from the Genesis Cycle and Spin Cycle Data Packs will no longer be legal for standard format Organised Play events, including tournaments. This does not, however, mean that you cannot use them in casual games -- just make sure you and your friends agree upon their use in your decks before you sit down to your games.
At the same time, many of the cards from the Genesis Cycle and Spin Cycle are scheduled to reappear in the Revised Core Set.
When it is released, the Revised Core Set will replace the Core Set in all Organised Play and tournament settings, and all the cards from the Genesis Cycle and Spin Cycle that appear in the Revised Core Set will once again be legal for Organised Play and tournament settings. If you have these cards, you will be able to include them in your Standard Play decks, even if you do not have the Revised Core Set.
Similarly, when the Revised Core Set is released, the cards from the classic Core Set that do not appear in the Revised Core Set will rotate out of the Standard Play card pool, but all reprinted cards will continue to be tournament-legal.
Those looking for some more specific details can find answers in this FAQ on the new core set and the rotation.