Due to the server suspension of Final Fantasy XI related to power conservation actions following the March 11th earthquake and tsunami that ravaged parts of Japan, Square Enix will be waiving the subscription fees for the month of April for active, paid accounts.

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From Playonline.com:

Due to the temporary suspension of the FINAL FANTASY XI game service, customers with active, paying subscriptions as of March 2011 will not be charged monthly FINAL FANTASY XI subscription fees ($12.95 + $1.00 per additional Content ID) for the April billing cycle. Below is a list of important notices for affected customers.

[Important Notes]
* Only customers who paid subscription fees for March 2011 are eligible. Customers registering new accounts or reactivating accounts in April are not eligible.
* Fees for any additional Content IDs purchased from April 1, 2011 onwards will not be waived.
* Any charges aside from monthly subscription and additional Content ID fees (e.g., expansion purchases, etc.) will not be waived.
* Customers who closed their accounts during March will be eligible. However, you must reactivate your account before the end of April; since subscription fees are only being waived for the month of April, we recommend you reactivate early in order to reap the full benefits of this offer.