The Davis Cup will experiment with a two day, best-of-three set, format in the lower tiers of next year's event.
The World Group, which features 2015 champions Great Britain, will continue to contest best-of-five set matches over three days.
But all captains will be able to select five rather than four man teams.
The trial for Zone Groups I and II will see two singles matches played on day one, with the doubles match plus two reverse singles matches on day two.
Other changes for the trial include no fifth rubber being played if the fourth match is decisive.