What are the current restrictions and requirements for internal flights in Thailand, such as Krabi to Bangkok?

Hello, I'm trying to find some official information about restrictions and requirements on internal flights, particularly krabi to Bangkok and back again...

My insurance are having to luck with contacting the embassy or authorities, surprise surprise. But they have heard that you might need an app? Anyone know anything about this? I'm guessing my insurance aren't going to take the word of a Facebook group although I would appreciate your advice anyway. Where can I find or who can I contact to get 'official' information? Obviously you're all probably laughing at this request as am, as I know as well as you do, that even they don't know know what's going on half the time. Thanks for your patience 🙏