Is it legal to be dismissed by SMS in violation of company discipline?

If the company has relevant rules and regulations that clearly stipulate the dissolution of labor relations in violation of company discipline and inform the workers in advance, it is legal.

According to the Labor Contract Law

Article 4 The employing unit shall establish and improve labor rules and regulations according to law, so as to ensure that laborers enjoy labor rights and perform labor obligations.

When an employing unit formulates, modifies or decides the rules and regulations or major issues directly related to the vital interests of workers, such as labor remuneration, working hours, rest and vacation, labor safety and hygiene, insurance and welfare, employee training, labor discipline and labor quota management, it shall discuss with the workers' congress or all employees, put forward plans and opinions, and negotiate with trade unions or employee representatives on an equal footing.

In the process of implementing rules and regulations and major issues, trade unions or employees have the right to propose to the employer and revise and improve them through consultation.

The employing unit shall publicize or inform the rules and regulations and major issues directly related to the vital interests of workers.