I have a Gretl file, last saved in 2017, that I now can't open. I have updated my Gretl to 2019-build. 

Error message:

First char of varname '_DAY' is bad
(first must be alphabetical)

a) can I download old version from somewhere?

b) is it an easy way to take a Gretl gdt-file and convert it to CSV?

Thanks in advance

Dagfinn Rime