As part of Hi-Rez's "upcoming developments" announcement today, they've decided to extend the period for which Conquest will be free for all players, sub or not:
We view the release of Global Agenda as the start of the journey and we are already working hard to continue delivering improvements, new features, and new content based on your feedback.
To prove it to you, we are going to extend the free-play period for Global Agenda Conquest while continuing to deliver features and content enhancements.
All players will continue to be able to play the Conquest features for the rest of February and March without a monthly subscription fee.
