Generally it's around 18 months out, and over the last few years DCL seems to have adopted this pattern for release dates on new cruises:
"Winter": first cruise in the new year up to April/May (not including spring Panama Canal and Transatlantic) – sometime between late September to early November
"Summer": cruises from about May to August/September (not including fall Panama Canal and Transatlantic) – mid February to early April.
"Fall": September until the end of the year (ending with the last cruise starting in the old year) – generally around May.
That said, there's no telling when/if cruising will start up anytime soon.
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