President Alassane Ouattara, who won re-election to a third term after initially stepping aside, said in October that Soro -- a former ally -- would be jailed for life.
Ouattara, now 79, had said after his second term he planned to make way for a new generation, but the sudden death of his chosen successor prompted him to seek a third term.
Soro, whose rebel forces controlled northern Ivory Coast in the 2000s, helped Ouattara militarily during the country's post-election crisis of 2010-11.
Incumbent Laurent Gbagbo demanded a recount of votes after the 2010 election, sparking a bloody conflict that claimed some 3,000 lives in the world's top cocoa producing country, formerly a beacon of stability and prosperity in the region.
Since then, Soro and Ouattara gradually drifted apart, until early 2019 when the rupture became final, analysts say, over Soro's presidential ambitions.
Soro was sentenced in April to 20 years in prison for "concealment of embezzlement of public funds", a conviction that torpedoed his candidacy.
Published/updated by ivorycoasttribune.com