Latest revisions of the AS1 and AS2 incorporate newly domestically developed modular explosive reactive armour, a modern battlefield management and fire-control system, a remote controlled weapon station and other updates.

[10] The imperative for modernization of Serbia's aging M-84 fleet presented the Military Technical Institute Belgrade and Serbian Defense Industry with numerous tasks and challenges.

Though a modernization program for the M-84 called M-84AB1 (later renamed to M-84AS) has been presented in 2004 by Serbia featuring several russian weapon systems, it has never seen mass adoption and only 10 M-84 were upgraded to this standard, probably due to the financial and political situation of Serbia at that time.

Since then tank designs around the world saw a number of fundamental improvements like the incorporation of explosive reactive armour, updated subsystems and optics or even active protection systems.

[12][13] The turret and hull are almost completely covered with domestic second-generation explosive reactive armour M19, providing increased protection from modern threats like top-attack or tandem-charge missiles according to the designers.

Early warning sensors for detection of radar,[17] laser designation[18] and launching of rockets are coupled with automatic delivery of Smoke grenade towards threat to achieve protection.

New type of RCWS with 12.7mm machine-gun is added so commander can operate safely inside turret.

[23][24] New tank gun 125mm[25] with modern thermal sleeve will be produced in Borbeni složeni sistemi factory and new ammunition[26][27] with better penetration and explosive characteristics including 125mm Airburst round.The APFSDS shell that is being issued to the tank is known to have 500mm of penetration at 2 kilometers range.