Luanda - Angola is expected to formally announce the end of President Jose Eduardo Dos Santos' controversial 37-year rule on Saturday, and name a successor to lead the ailing African oil-producing country.News of the veteran leader's impending retirement, announced on state radio on December 2, has made front page news in Angolan newspapers all week.But the ruling Popular Movement for the Liberation of Angola (MPLA), in power since 1975, has officially remained silent on the matter.On Saturday, on the 60th anniversary of its founding, the party is expected to confirm that Dos Santos, 74, will not seek another term as president in the 2017 party elections.It will also likely announce that he will be succeeded as head of the party by his current defence minister, Joao Lourenco, 62.Angola does not directly elect a president, but rather the leader of the winning party automatically becomes head of state.Complete surprise In all likelihood, the retired general Lourenco will succeed Dos Santos - one of the longest ruling leaders in Africa - after the party elections next August.The departure, announced in a closed-door meeting of the MPLA's central committee last week, does not come as a complete surprise.Dos Santos himself announced in March his intention to end his political career."President dos Santos had been planning to step down in 2018," said Alex Vines, Africa programme director at the British think tank Chatham House."But I think a combination of Angola's economic conditions and less good health brought his plans forward."After years of spectacular growth thanks to an oil boom, like many crude-producing nations Angola has suffered a sudden downturn in the last two years due to a prolonged drop in oil prices.Last week, national oil company Sonangol, managed by Dos Santos' daughter Isabel, announced it would not be paying out dividends to the state this year - a first for the country's main source of foreign currency.'Nothing will change' While it will be a new page in the history of Angola, the departure of the former Marxist guerilla fighter is unlikely to shake up the running of the country.This is to the chagrin of critics who have been denouncing Dos Santos' "dictatorship" for years."Nothing will change with people who, when they could have, didn't dare -- whether out of fear or self-interest -- to make a difference," said journalist William Tonnet, a critic of Dos Santos.Expected successor Lourenco is an ex-artillery general who was trained in the former Soviet Union. He is seen as a true son of his party, as is interior minister Bornito de Sousa, who is expected to become his deputy."These are two apparatchiks, two pure products of the party who remain under its control," said Benjamin Auge of the French Institute of International Relations."The room to manoeuvre will be extremely limited. They will defend the president's record, without starting a revolution."However, Angola-watchers notice both men do not have ties to the oil industry, a sector considered to be closely guarded by the president's family.Expression of discontent "Joao Lourenco is one of those rare leaders in the MPLA who hasn't dirtied his hands in this corruption business," said activist Nuno Alvaro Dala, who was recently convicted and then pardoned for an alleged coup attempt.Some have suggested that Dos Santos's retirement was purposefully instigated by a hostile faction within the MPLA.The announcement could be "the expression of discontent within the party, particularly over the position of the president's children," said Didier Peclard, a professor at the University of Geneva. "If that were the case, then hypothetically it could be a way of precipitating a transition."Award-winning journalist and writer Rafael Marques refuses to believe this, and disputes the idea of a more palatable faction within the inner circle of the MPLA."Angolans will move from one dictator to the next," he said. "Change is not coming tomorrow."