No doubt, NK has breached Art. 62's clear language (for rational or irrational reasons):

62. The Articles and Paragraphs of this Armistice Agreement shall remain in effect until expressly superseded either by mutually acceptable amendments and additions or by provision in an appropriate agreement for a peaceful settlement at a political level between both sides.
and some propose (based on news reports of "what should be done") to breach Art. 15 & 16's clear language (for the rational reason of preventing export of nuclear weapons):

15. This Armistice Agreement shall apply to all opposing naval forces, which naval forces shall respect the water contiguous to the Demilitarized Zone and to the land area of Korea under the military control of the opposing side, and shall not engage in blockade of any kind of Korea.

16. This Armistice Agreement shall apply to all opposing air forces, which air forces shall respect the air space over the Demilitarized Zone and over the area of Korea under the military control of the opposing side, and over the waters contiguous to both.
Ultimately, discussion of the Armistice will be trumped by each country's decision, based on its enlightened self-interests, of its need to invoke its rights under UN Article 51:

Article 51 of the Charter of the United Nations

Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain inter- national peace and security. Measures taken by Members in the exercise of this right of self-defence shall be immediately reported to the Security Council and shall not in any way affect the authority and responsibility of the Security Council under the present Charter to take at any time such action as it deems necessary in order to maintain or restore international peace and security.
whether those rights be an "offensive defense", or solely defense of territory as is the current Russian response.