I received this letter as an e-mail attachment from the german embassy today. It seems really short and I'm not sure if it's enough to process the visa extension in Bangkok. And I'm here on an ED visa which will expire on April 4th. Is there someone who got his extension for an ED visa?
TLDR : Answer Summary
The letter from the German embassy may be sufficient for processing your ED visa extension in Bangkok. Experiences shared by others indicate that while few extensions are granted, some have had success. It's advisable to present the letter, which is official and personalized, to immigration, along with your school's documentation. However, be aware that the extension might only be for up to 30 days.