What was the purpose of the most recent amendment to the constitution

The purpose of the latest amendment is to prohibit any law from allowing an increase or decrease in the salary of members of Congress from coming into effect until the next term of office commences.

Explanation:

The Twenty Seventh Amendment to the U. S. Constitution is the latest to be ratified, thus getting adopted, even though it was proposed along with the amendments which became the Bill of Rights in 1789.

The Twenty-seventh Amendment (Amendment XXVII) to the United States Constitution prohibits any law that increases or decreases the salary of members of Congress from taking effect until the start of the next set of terms of office for representatives.