As a general rule, it's best to list deck releases and other time-specific events using UTC/GMT and let everyone else convert them as needed. There are places that change on and off "summer/Daylight Saving" time at different dates and other places that don't change at all, so it reduces confusion to use a standard like UTC.
So, if I'm not mistaken,
4pm British Summer Time is
15:00 UTC/GMT as well as
11am Eastern Daylight Time and
8am Pacific Daylight Time...