When I'm migrate to MW 1.31-rc.0, using REL1_31 (2d2c8fc) of VE, I got:
mod_fcgid: stderr: PHP Warning: Illegal string offset 'revid' in /srv/mediawiki-1.31-rc.0/w/extensions/VisualEditor/includes/ApiVisualEditor.php on line 351, referer: https://xxx.org/w/index.php?title=%E9%A6%96%E9%A1%B5&veaction=editsource
Steps to reproduce:
Using 2017 new editor to edit any page.