Please answer a question about the following article about Chihuahua (state):

The state united behind the Plan of Ayutla and ratified the new constitution in 1855. The state was able to survive through the Reform War with minimal damage due to the large number of liberal political figures. The 1858 conservative movement did not succeed in the state even after the successful military campaign of the conservative Zuloaga with 1,000 men occupied the cities of Chihuahua and Parral. In August 1859, Zuloaga and his forces were defeated by the liberal Orozco and his forces; Orozco soon after deposed the state governor, but had to flee to Durango two months later. In the late 1860s the conservative General Cajen briefly entered the state after his campaign through the state of Jalisco and helped establish conservative politicians and ran out the liberal leaders Jesús González Ortega and José María Patoni. Cajen took possession of the state capital and established himself as governor; he brooked no delay in uniting a large force to combat the liberal forces which he defeated in La Batalla del Gallo. Cajen attained several advantages over the liberals within the state, but soon lost his standing due to a strong resurgence of the liberal forces within the state. The successful liberal leaders José María Patoni of Durango and J.E. Muñoz of Chihuahua quickly strengthened their standing by limiting the political rights of the clergy implementing the presidential decree. The state elected General Luis Terrazas, a liberal leader, as governor; he would continue to fight small battles within the state to suppress conservative uprisings during 1861.

In which year was the new constitution ratified?
1855