Hi,
For anybody who is looking for an appointment to renewal their license in Bangkok in December and January their are still appointments available at Bangkok Transportation Office Area 1 Bang Khun Thian.
I did make an appointment just on Monday via online booking and every day this and next month where still available.
Super plus is they also issue both types of IDL as of act 1949 and 1968. Each cost 505 Baht. I got both of them but I don't know if it is necessary to have both.
Countries included in the agreement can be found here: https://treaties.un.org/pages/ViewDetailsIII.aspx?src=TREATY&mtdsg_no=XI-B-19&chapter=11
Cheers