In what year was Paraguay's flag first adopted?

In what year was Paraguay's flag first adopted? Paraguay's current flag was first adopted in 1842.

The design is a horizontal red, white, and blue triband. It was unified by Congress on 25 November 1842, during the leadership of Carlos Antonio López and Mariano Roque Alonso. The adoption also established distinctive emblems on each side: the national coat of arms on the obverse and the treasury seal on the reverse.

This date refers to the current tricolor, not the first banner ever used in Paraguayan territory. A blue flag with a white six-pointed star appeared in 1811, while other designs were used between 1812 and 1842. That history makes 1811 and 1826 plausible-looking but incorrect choices for this question.

Paraguay’s flag was revised in 2013 to move its design closer to earlier forms. It remains especially unusual because its two sides display different central emblems.