afaik in some countries its not required (switzerland?) and in others it depends on the number of years the person worked in company. i think it depends on the country.

No severance pay required in Switzerland but there will be a mandatory one month to three months notice period. A company can decide to send their workers home earlier but they would still be required to pay salary for that period. Though when laying of 25% there will be some additional government requirements as it would be classified as a mass-layoff and will need a social plan.