File Photo: An Egyptian Military Courts Complex (Ahram)
The court decided to reject all appeals and uphold the verdict for all but two defendants, whose sentences were reduced to 15 years, Khaled El-Masry wrote on Facebook.
A life sentence in Egypt is capped at 25 years' imprisonment.
In June 2019, a military criminal court handed down life sentences to the 32 defendants in the case. Of the more than 290 defendants originally appearing in the case, 264 were sentenced to between three and 15 years in jail.
The defendants were charged with setting up terrorist cells that committed crimes including planning to assassinate El-Sisi and Saudi Arabia's former crown prince and interior minister, Mohammed bin Nayef.
Excerpts from a public prosecutor's investigation in 2016 published in local media revealed the defendants were plotting to assassinate El-Sisi and the former crown prince while they were on pilgrimage to the Islamic holy city of Mecca in 2014.
It became locally known as the "El-Sisi assassination" case.
The suspects were arrested on charges of belonging to an affiliate of the terrorist-designated Islamic State group in North Sinai, where security forces have for years fought against terrorists.
Some were charged with the targeted killing of three judges in North Sinai in 2015, while others were charged with the targeting of tourists and security forces.
Terrorists in North Sinai attacked Egyptian forces after the 2013 ouster of Egyptian president Mohamed Morsi of the Muslim Brotherhood amid mass protests against his rule.
Since February 2018, the authorities have been conducting a nationwide operation against terrorists in North Sinai and the country's Western Desert.
* This story was edited by Ahram Online