Migration v7 to v8 LTS: Missing field l10n_source
I tried to migrate a system from 7.6 to 8.7.20. If I start the Upgrade Wizard in the install tool, I got an error, that field l10n_source is unknown to table tt_content.
The issue lies in FillTranslationSourceField, the checkForUpdate is called which assumes that the field exists but it isn't created yet, this will be done by running the "Update database schema: Create tables and fields" part. Which I can't do cause of the error.