According to information published by the Slovenian Press Agency on September 19, 2022, German Chancellor Olaf Scholz and Slovenian Prime Minister Robert Golob on Monday, September 19, agreed on the transfer to Ukraine of 28 M-55S main battle tanks from the Slovenian army military inventory in exchange for German military vehicles.
On April 2022, Slovenia had already approved the delivery of its fleet of M-84 main battle tanks in exchange for German-made Marder tracked armored IFVs and Fuchs 6×6 armored vehicles. Slovenia also provided 35 BVP M-80A tracked armored IFVs (Infantry Fighting Vehicles) to Ukraine.
In mid-1990 Slovenia started a program to upgrade its old T-55 MBTs (Main Battle Tanks) to a new standard locally known as the M-55S. The first M-55 tank was completed in 1997 with final deliveries being made to the Slovenian Army in 1999.