Players with an existing subscription will also retain the subscription and won’t need to do anything extra to keep it; it can still be cancelled at any time, although presumably that will prevent you from re-subscribing. There will also be no more subscriber locks on test server access. So it just means no new subscribers to the game, just everyone playing free. Or, you know, the same price as always.
Star Trek Online, although you could argue it’s a somewhat lateral shift. The game will no longer be offering monthly subscriptions from its website, replacing them with a “starter pack” that allows you to permanently unlock most of the same perpetual benefits for a one-time fee. Lifetime subscriptions will remain as they always have and will offer the same benefits as always, while veteran rewards will still be available to those who have earned them.
Source: Official Site; thanks to Jake for the tip!