There are many new technological advancements that have been achieved in the last 500 years including blasters, stealth, and MCPS.
Tendrando Arms, Numerous
Since the time of the Sith-Imperial War, blaster technology has approved along a fairly predictable path. Namely, blasters are now more powerful, have a longer range and have more shots per blaster pack.
The technology has steadily improved through the last five hundred years due in large part to the buyout of BlasTech by Tendrando Arms. Tendrando researchers compared research notes and were capable of making various improvements. They now produce pistols, heavy pistols, rifles, light repeaters, heavy repeaters, etc.
During the Dark Nest Crisis of the early years following 0 BBY, a stealth fighter known as the Stealth-X was create. The X-wing shoot-off utilized a special tibanna gas to hide engine exhaust as well as a special coating to stop sensor sweeps. From that point on, an arms race of sort between developers occurred with a new technology coming out every couple decades which would trump the opposing technology. For example, in 65 ABY, Sinear Fleet Systems succeeded in creating a sensor capable of detecting Stealth-X's. Over the next forty years, the sensor technology improved rapidly almost the point of making such stealth coatings useless. In 145 ABY, the stealth industry upgraded the technology, starting the process all over again. By 600 ABY, the technology on each side has become incredibly sophisticated and sensors have a 38% chance of detecting stealth ships at average range.
Metal-Crystal-Phase-Shifter (MCPS) Edit
Maw Irregular Fleet/ Corellian Government
40 ABY, 64 ABY
The MCPS utilized in Daala's Maw Irregular Fleet deserves a mention due to its unorthodox abilities and potential destructive ability. The weapon saw a tremendous amount of use during Daala's reign in the GA however, in 64 ABY, a device was created that used an electro-magnetic field to cover a ships' hull. The device was easily installed and essentially rendered MCPS's useless. By 75 ABY, the MCPS had been abandoned.