I had a nice conversation with the Legal Counsel of VIZ Media, and it was confirmed that the letter was indeed fake.
Manga will continue to be released here until the day if/when they choose to send the real one. There will be delays on today's releases as I finish up a few things that require my attention. Thanks for your patience/support.
If you download manga from this website and enjoy it, please consider buying the official volumes when they're released in your area -- They make use of the original artwork, have professional translations, and are printed on higher quality paper for the best possible reading experience.