The packages that attempt to use Org functions outside of Org mode only work by chance. The warning just makes the problem more clear - it was added to tame an inflow of bug reports that had nothing to do with Org mode itself and were caused by trying to use Org functions improperly.
If things happen to be working for your setup as a user, nothing is changed in Org 9.7-pre except this warning being dislpayed. So, feel free to hide it locally.
It means that you have part of the Org libraries loaded from built-in Org mode version and part of the Org libraries loaded from a newer Org mode version that is installed on top.
You can try (1) ensure that you setup the correct load-path for Org mode early in your config (2) reinstall; (3) if does not help, reinstall from emacs -Q. See Update On The Org-9.6 Problem | Irreal
Thanks a lot! I have another question. When I use org-fragtog in markdown-mode for some latex, it warning this, is this one same as the warning above? the warning is infinite so I can’t edit md file anymore.
That’s one of the manifestations using Org parser in non-Org buffers - Org relies upon certain buffer-local variables to operate; and these variables are not set property in non-Org buffers.
Why are you even using org-fragtog in md buffers? org-fragtog is designed for Org mode, not for md.
You may report this to org-fragtog authors. From the point of view of Org mode, parsing non-Org buffers is not supported. If other packages need to parse something as Org mode, they need to arrange the buffer being parsed to use Org mode. If it is not done, the errors like you encountered may appear. Moreover, user-customized Org parser settings will not apply - for example, custom TODO keywords cannot be parsed.
