Your comments

Thank you very much, Vlad. I dropped the table and used your query to recreate it. The advanced options for web links are available again.

Thank you for your respons Vlad. I run MySQL on a different machine that runs Ubuntu 18.04 as well. MySQL version is 5.7 (Ver 14.14 Distrib 5.7.26, for Linux (x86_64) using EditLine wrapper).

There is an error in the mysql_errors.log:

/?module=weblinks┬žion=ajax&page=update (POST)
2019-06-10T23:24:38+02:00 - UPDATE `df_modules_weblinks` SET `date_modified`=NOW(),`password`=NULL,`expiry`='2019-06-14 00:00:00',`download_limit`=NULL,`allow_uploads`=0,`allow_downloads`='1',`show_comments`=0,`show_comments_names`=0,`require_login`=0,`force_save`='1',`notify`=0,`download_terms`=NULL WHERE (id = '14')
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'require_login' in 'field list'

I am not sure why this column is missing. Do you have a suggestion how to repair the mysql structure?