Oldon, an online journalist, was arrested upon his arrival at the Hargeisa airport after he met Somalia’s new President Mohamed Abdullahi Mohamed in February.
Oldon was sentenced Saturday at a regional court in Hargeisa, Somaliland’s capital.
Somali media organizations have long said Somalia’s old penal code written in 1960 is designed to silence journalists and curtail freedom of expression.
Oldon’s family told reporters they would appeal the verdict.
Somaliland broke away from Somalia in 1991. No country so far has recognized it as independent.