Hi,
As per Microsoft the validity is only for 12 months and after that you have to move to PAYG -
"If you exhaust your available credit before 12 months and you want to continue to use Azure, you can upgrade to a pay-as-you-go subscription in the Azure portal. If you do not upgrade, your Azure subscription becomes disabled. If you’re at the end of 12 months, you can renew your subscription by signing up again for the offer."
Please check the FAQs and terms over here - https://learn.microsoft.com/en-us/azure/education-hub/azure-dev-tools-teaching/program-faq
Hope this helps.
JS
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