Changes from the T-72M include a new dual-axis stabilized fire-control system, reactive armour, a more powerful engine, transmission and new automatic loader.

Many of the elements were used to upgrade existing fleets of T-72 tanks in countries including the Czech Republic (T-72M4 CZ), Georgia (T-72SIM-1), and India (T-72 Ajeya Mk.

[citation needed] In the late 1980s, the Polish Army modernized all of its obsolete T-55 tanks to the T-55AM Mérida standard.

The successful conversion convinced the General Staff that similar modernization programs could be applied to other Soviet-designed tanks made in Poland and used by the Polish Armed Forces.

However, initially, the work progressed at a very slow pace, mainly because the Polish General Staff was also considering the purchase of a newer version of the T-72 (T-72S) or the modern T-80.

[citation needed] The basic aim of the T-72 conversion was to adapt it to the reality of modern warfare and fix its most visible deficiencies.

[citation needed] Starting in July 1991, T-72 modernization programs were implemented by the Bumar-Labedy factory, which had been producing T-72s under Soviet license.

In 1993, the Polish Defense Ministry ordered 20 PT-91 tanks, to be used for field trials and armed forces tests.

[citation needed] The new ERAWA [pl] dynamic armour, developed by the Poland Military-Technical Institute, increased the main battle tank's protection from high-explosive anti-tank (HEAT) projectiles and missiles.

Experiments showed that the ERAWA dynamic defense decreases the high-explosive jet impact depth by 50–70% and that of penetrator (APFSDS) projectiles by 30–40%.

Furthermore, ERAWA's explosive containers do not detonate when hit by a shot of up to 30 mm calibre or by shell or mine fragments, or when covered in burning napalm or petrol.

Furthermore, it informs the commander when the sighted fire becomes ineffective from excessively high cross-country speed or other reasons.

[citation needed] The Drawa (uzbrojenie) [pl] fire control system, developed by Polish engineers, contains the PCD gunner's day sight and the TES thermovision night sight developed by the Israeli company El-Op, the POD-72 commander's combined day-night passive observation and aiming sight, a ballistic computer, a laser rangefinder, and a data system processing information for the ballistic computer.

[10] Development variant with a PZL-Wola S-1000 1,000 hp engine with mechanic transmission and a number of other minor changes.

[11] The biggest advantage is a new gun stabilization system that provides a significant increase in accuracy when the tank is on the move.

The PT-72U is equipped with a remote-controlled weapon station armed with a 12.7 mm machine gun mounted to the crew commander hatch.

The chassis equipment includes an auxiliary power generator (APU), air conditioning, a new steering system with shuttlecock and a PCO KDN-1 Nyks day/night reversing camera.

[citation needed] The additional composite armour of both the hull and the turret is expected to increase survival of the tank on the battlefield, as is the installed PCO SSP-1 OBRA-3 universal self-propelled vehicle system and two 6-tube intermittent grenade launchers.

Among the chassis, equipment included the auxiliary power generator (APU), the modernized rotary car charger, the PNK-72 "Radomka" night-vision, and PCO KDN-1 Nyks night-time reversing camera.

[citation needed] Increased firepower is planned to be achieved by installing a 125 mm 2M46MS caliber Slovak cannon with a barrel length of 48 calibres.

Significantly, the PT-91M2 demonstrated a SAVAN-15 French fire control system (SAVAN-15) from Safran, previously used in PT-91M tanks in Malaysia.

Standard equipment includes: crane with telescopic jib that can lift a maximum load of fifteen tonnes, front-mounted stabilizing dozer blade, main and secondary winches.

The Loara is an autonomous fire unit capable of performing its tasks independently or acting as a component of a wider air defense system.

Two propositions were submitted, one by Bumar which provided a project with modified frontal armour, different mortar and sporting a Leclerc–like a turret with the 2A46 main gun.

[citation needed] The Krab (Polish for Crab) is a 155 mm self-propelled howitzer designed by HSW S.A. with an OBRUM's UPG-NG chassis (a heavily modified variant of the SPG-1M vehicle) which utilizes only a handful of components from the PT-91 program such as the road wheels, suspension and S-12U power plant.

It combines these with a licensed AS-90M Braveheart turret armed with a 52-calibre gun and WB Electronics Artillery Fire Control System Topaz.

[24] In 2014, this configuration was abandoned due to manufacturing flaws (microfractures detected in the vehicle's welded steel plates), numerous reliability concerns related to the automotive performance of the chassis and the loss of the Polish manufacturing line for the S-12U engine, and was replaced by the Korean-made K9 tracked chassis.

[citation needed] In 2002, the 10th Armoured Cavalry brigade received Leopard 2A4 tanks donated to Poland by Germany.

[citation needed] Before the start of the war in Ukraine, Polish Land Forces operated 4 battalions of PT-91 tanks.

[citation needed] In 2007–2009, Bumar Łabędy delivered to Malaysia 48 PT-91M and 15 support vehicles (6 WZT-4 {WZT-91M} armoured recovery vehicle, 3 MID-M {MID-91M} engineering tank, 5 PMC Leguan {PMC-91M} - armoured vehicle-launched bridge and one SJ-09 driver training tank), ammo, spares and support for US$370 million.