In the 2010s, Armenia embarked on an expansive modernisation programme of its air defences to keep up with Azerbaijan's expanding drone arsenal and to address the obsolescence of its existing surface-to-air missile (SAM) and radar systems. Although acquisitions like the Tor-M2KM and Buk-M1-2, and Russian jamming equipment such as the Repellent-1 and Avtobaza-M would attract the most attention, overhauls and upgrades performed to its older systems occurred as well. This included SAM systems like the 2K11 Krug, 2K12 Kub and the S-125, all of which dated from the 1960s.